But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you. Being then made free from sin, ye became the servants of righteousness.
~ Romans 6:17-18

But grow in grace, and in the knowledge of our Lord and Saviour Jesus Christ. To him be glory both now and for ever. Amen.
~ 2 Peter 3:18

Pneumatologia (Of the Holy Spirit), by John Owen. An excerpt.

From what has been proved, it is evident that the work of sanctification is a progressive work, that it gradually carries holiness on towards perfection in us. It is neither worked nor completed at once in us, as regeneration is; nor does it cease upon any attainments or condition of life, but is thriving and carried on. A river continually fed by a living fountain could as soon end its streams before it comes to the ocean, as a stop could be put to the course and progress of grace before it ends in glory. For “the path of the just is like the shining light, that shines more and more unto the perfect day,” Pro 4.18. So too their path is like the morning light, the way in which they are led and conducted by the Holy Spirit: once it appears, even though it may sometimes be clouded, it does not fail until it arrives at its perfection. And just as the wisdom, patience, faithfulness, and power which the Holy Spirit of God exercises in this are inexpressible, so these are constantly admired by all those who have an interest in them, as described by the psalmist, Psa 66.8-9, 31.19.811

Who is there that has made any diligent observation of his own heart and ways, and what the workings of the grace of God have been in and towards him to bring him to the stature and measure to which he has arrived, that does not admire the watchful care and powerful workings of the Spirit of God in this? If the principle of our holiness is weak and infirm in us, it is nonetheless in us. In some, it is to so low a degree, it is often imperceptible to them. The Spirit preserves and cherishes even this, so that it will not be overpowered by corruptions and temptations. Among all the glorious works of God, next to that of redemption by Jesus Christ, my soul most admires this about the Spirit: His preserving of the seed and principle of holiness in us, like a spark of living fire in the midst of the ocean, against all corruptions and temptations with which it is impugned.

Many breaches are made in our course of obedience by the incursions of actual sins; the Spirit cures and fixes these, healing our backslidings and repairing our decays. And he acts the grace that is received by constant fresh supplies. The one who does not diligently observe the ways and means by which grace is preserved and promoted, lacks much of the comfort and joy of a spiritual life; and it is no small part of our sin and folly when we are negligent in this.

No doubt, all believers are convinced of this in some measure, not only from the testimonies given of it in the Scripture, but also from their own experience. There is nothing they may more distinctly learn it from than the nature and course of their prayers, with the workings of their hearts, minds, and affections in them. Let profane persons deride it while they please, it is the Spirit of God, as a Spirit of grace, that enables believers to pray and make intercession according to the mind of God. And in this, because he is the Spirit of supplications, he copies out and expresses what he works in them as the Spirit of sanctification. In teaching us to pray, he teaches us what and how he works in us; and if we wisely consider his working in our hearts by prayer, we may understand much of his working upon our hearts by grace. It is said that “he who searches the hearts” (that is, God himself) “knows the mind of the Spirit,” in the intercessions he makes in us, Rom 8.27. There are secret powerful operations of the Spirit in prayer that are discernible only to the great Searcher of hearts. But we should also inquire and observe, so far as we may, what he leads us to and guides us about — which is plainly his work in us. I do not think that the Spirit works supplications in us by an immediate, supernatural, divine afflatus, as he inspired the prophets of old; they often did not understand the things they uttered, but diligently inquired into them afterward. But I do say (let the proud carnal world despise it while they please, and at their peril) that the Spirit of God, in the prayers of believers, graciously carries out and acts their souls and minds in desires and requests which, as to their subject matter, are far above their natural contrivances and invention. The one who has not experienced this, is a greater stranger to these things than it will, at length, be to his advantage. By a diligent observance of this, we may know what kind and nature the work of the Holy Ghost is in us, and how it is carried on.

For how, in general, does the Holy Spirit teach us and enable us to pray? It is by these three things:

1. By giving us a spiritual insight into the promises of God and the grace of the covenant, by which we know what to ask upon a spiritual view of the mercy and grace that God has prepared for us.

2. By acquainting us with and giving us an experience of our wants, with a deep sense of them, such that we cannot bear it without relief.

3. By creating and stirring up desires in the new creature for its own preservation, increase, and improvement.

And corresponding to these things, consists the Spirit’s whole work of sanctification in us; for it is his effectual communication to us of the grace and mercy prepared in the promises of the covenant, through Jesus Christ. Hereby he supplies our spiritual wants, and sets the new creature in life and vigor. So our prayers are an extract and copy of the work of the Holy Spirit in us, given to us by the Spirit himself. And therefore, by whomever he is despised as a Spirit of supplication, he is despised as a Spirit of sanctification also. Now consider, what is it that you most labor about in your prayers? Is it not that the body, the power, the whole interest of sin in you may be weakened, subdued, and at length destroyed? Is it not that all the graces of the Spirit may be daily renewed, increased, and strengthened, so that you may be more ready and prepared for all the duties of obedience? And what is all this for, if not that holiness may be gradually progressive in your souls, that it may be carried on by new supplies and additions of grace, until it comes to perfection?

It will be said by some, perhaps, that by their best observation, they do not find in themselves or in others, that the work of sanctification is constantly progressive, or that holiness grows and thrives this way wherever it is found in sincerity. For themselves, they have found grace more vigorous, active, and flourishing in their former days than recently; its streams were fresher and stronger at the spring of their conversion than since they have found their course. From this come those complaints among many about their leanness, their weakness, their deadness, their barrenness. Nor were many of the saints in the Scripture without such complaints. And many may cry, “Oh if only it was the same as in our former days, in the days of our youth!” Complaints of this nature abound everywhere. Some are ready to conclude from this, that either sincere holiness is not as growing and progressive as pretended, or that in fact they have no interest in it. The same may be said by a diligent observation of others, both churches and single professors. What evidence do they give that the work of holiness is thriving in them? Does grace not appear instead, to be retrograding and under constant decay?

I will consider and remove this objection as far as needed, so that the truth we asserted does not suffer from it and we are left with an empty theory; and also that those who do not fully comply with holiness, are not altogether discouraged. I will do this in the ensuing rules and observations.

1. It is one thing to consider what grace or holiness is suited to in its own nature, and what the Spirit’s ordinary or regular way of proceeding is in the work of sanctification, according to the tenor of the covenant of grace. It is another thing to consider what may occasionally fall out by indisposition and irregularity, or by any other obstructing interposition in those persons in whom the work is wrought. Under the first consideration, the work is thriving and progressive; in the latter, the rule is liable to various exceptions. A child that has a principle of life, a good natural constitution, and suitable food, will grow and thrive; but if that child has obstructions from within, or distempers and diseases, or falls and bruises, it may be weak and wasted.

When we are regenerated, we are like newborn babes, and ordinarily, if we have the sincere milk of the word, we will grow by it. But if we give way to temptations, corruptions, negligences, or conformity to the world, is it any wonder if we are lifeless and wasted? It suffices to confirm the truth of what we asserted, that everyone in whom there is a principle of spiritual life, who is born of God, and in whom the work of sanctification has begun — if it is not gradually carried on in him, if he does not thrive in grace and holiness, if he does not go from strength to strength — it is ordinarily from his own sinful negligence and indulgence of carnal lusts, or from his love of this present world. Considering the time we have had and the means we have enjoyed, what full-grown, what flourishing plants many of us might have been — in faith, love, purity, self-denial, and universal conformity to Christ — who are now weak, withering, fruitless, and sapless, and scarcely to be distinguished from the thorns and briers of the world! It is time for us to cast off every weight and the sin that so easily besets us,Heb 12.1 to stir ourselves up by all means to a vigorous recovery of our first faith and love, with an abundant growth in them, rather than complain that the work of holiness does not go on. And we should do this before our wounds become incurable.

2. It is one thing to have holiness really thriving in any soul; and it is another for that soul to know it and be satisfied in it; these two things may be separated. There are many reasons for this. But before I name them, I must premise one necessary observation —

This rule is proposed for the relief of those who are at a loss about their own condition, and do not know whether holiness is thriving in them or not; or for those who have no concern in this, who may at some point, if they please, give themselves an account of how these matters are going with them and on what grounds. For if men indulge any predominant lust; if they live in the neglect of any known duty or in the practice of any way of deceit; if they allow the world to devour the choicest increase of their souls; if they allow formality to eat out the spirit, vigor, and life of holy duties; or if any of these persist in a remarkable manner — I have nothing to offer them to manifest that holiness may thrive in them although they do not discern it; for undoubtedly it does not.

Nor are they to entertain any hope but this: that while they abide in such a condition, holiness will decay more and more. Such men are to be awakened violently, like men falling into a deadly lethargy, to be snatched like brands out of the fire,Zec 3.2 to be warned to recover their first faith and love, to repent and do their first works, Rev 2.4-5 lest their end be darkness and sorrow forevermore.

But as for those who walk with God humbly and in sincerity, there may be various reasons why holiness may be thriving in them, and yet they do not discern it. Therefore, though holiness is worked within ourselves, and only there, there may yet be seasons in which sincere, humble believers may be obliged to believe there is an increase and growth of holiness in them, when they do not perceive it in such a way as to be aware of it; for —

(1.) Because it is the subject of so many gospel promises, it is a proper object of our faith, or a thing that is to be believed. The promises are God’s explanations of the grace of the covenant, both as to its nature and the manner of its operation. And these promises do not abound in anything more than this: that those who partake of grace will thrive and grow by it. It will be declared afterward what limitations these promises are bounded with, and what is required on our part so that we may have them fulfilled towards us. But their accomplishment depends on God’s faithfulness, and not on our sense of it. Therefore, where we do not openly lay an obstruction against it, as in the case just mentioned, we may, we ought to believe that they are fulfilled towards us, even though we are not continually aware of it. And,

(2.) It is our duty to grow and thrive in holiness; and we are to believe that God will help us in what he requires of us; and he does so, whatever our present sense and apprehension of it may be. On these grounds, in my judgment, the one who can believe the growth of holiness in himself, even though he has no sensible experience of it, is in as good and perhaps a safer condition than the one who, through the vigorous working of spiritual affections, is most aware of this. For it is certain that such a person does not by any willful neglect or indulgence of any sin, obstruct the growth of holiness — for the one who does obstruct it cannot believe that holiness thrives in him or that it is carried on, whatever his presumptions may be; — and thus the life of faith, of which this holiness is a part, is in every way a safe life. Besides, such a person is not in danger of a vain elation of mind and carelessness on that account, as others may be. For when we live by faith, and not at all by sense,2Cor 5.7 we will be humble and fear always. Not finding in himself the evidence of what he most desires, a believer will be continually careful not to drive it farther from him. But the reasons for this difficulty are:

[1.] The work itself, as declared at large before, is secret and mysterious. And therefore, there is in some (I hope in many), the reality and essence of holiness, who can yet find nothing of it in themselves nor perhaps in anyone else, but only in Jesus Christ; those who have a lively understanding of the fear of the Lord. And so holiness may in the same secret manner, thrive in its degrees in those who yet do not perceive it. There is nothing in our whole course that we should be more awake to than a diligent observation of the progress and decays of grace. For just as knowledge of them has the same importance to us as our duties and comforts, so they are hard and difficult to discern; nor will they be as truly for our good and advantage without our utmost diligence and spiritual wisdom in observing them.

Hence, as we observed before, it is frequently compared in the Scripture to the growth of plants and trees (Hos 14.5-6, Isa 44.3-4). Now, we know that in those which are the most thriving and flourishing, though we may perceive that they are grown, we cannot discern their growing. And so the apostle tells us that as the “outward man perishes, so the inward man is renewed day by day,” 2Cor 4.16. The outward man perishes by those same natural decays by which it continually tends toward death and dissolution; and many of us know how these insensible decays are hardly discerned unless some great and violent disease befalls us. We know that we are enfeebled and weakened by age and infirmities, rather than perceiving when or how it happens. This too is how the inward man is renewed in grace. It is by such secret ways and means as that its growth and decay are hardly apprehended. And yet someone who is negligent in this inquiry, who walks at all uncertainly with God, does not know where he is along his way, whether he is nearer or farther away from his journey’s end than he was before. Write that man down as a fruitless and wasted Christian, who does not call himself to account for his increases and decays in grace. David knew this work was of such great importance that he would not trust himself and ordinary assistances to discharge it; but he earnestly calls on God to undertake it for him, and to acquaint him with it, Psa 139.23-24.812

[2.] There may be some perplexing temptations that befall the mind of a believer, or some corruption may take advantage to break loose for a season (maybe for a long season), which may gall the soul greatly with its suggestions, and thus trouble, disturb, and disquiet it so much that it will not be able to make a right judgment about its grace and progress in holiness.

A ship may be so tossed in a storm at sea, that the most skillful mariners may not be able to discern whether they are making any headway in their intended course and voyage, even while they are carried onward with success and speed. So too, grace in its exercise is principally engaged in opposition to its enemy which it conflicts with; and so its thriving in other ways is not discernible. If it were asked how we may discern when grace is exercised and thrives in opposition to corruptions and temptations, I say that just as great winds and storms sometimes contribute to the fruit-bearing of trees and plants, so corruptions and temptations contribute to the fruitfulness of grace and holiness. The wind comes upon the tree violently, ruffles its boughs, maybe breaks some of them, beats off its buds, loosens and shakes its roots, and threatens to cast the whole tree to the ground — but by this means the earth is opened and loosed around it, and the tree gets its roots deeper into the earth, by which it receives more and fresher nourishment. This renders it fruitful, even though perhaps it does not bring forth fruit visibly till a good while later. In the assaults of temptations and corruptions, the soul is woefully ruffled and disordered; its leaves of profession are greatly blasted, and its beginnings of fruit-bearing are greatly broken and retarded. But, in the meantime, it secretly and invisibly spreads out its roots of humility, self-abasement, and mourning, in a hidden and continual laboring of faith and love after that grace. Holiness increases by this really, and a way is made for future visible fruitfulness: for —

[3.] God, in his infinite wisdom, manages the new creature, or the whole life of grace, by his Spirit. He so turns its streams, and so renews and changes the special kinds of its operations, that we cannot easily trace his paths in this. And therefore we may often be at a loss about it, not knowing well what he is doing with us. For instance, it may be that the work of grace and holiness has greatly exerted and evidenced itself in the affections, which are renewed by it. Hence persons have a great experience of readiness for, and delight and cheerfulness in, holy duties — especially those affections of having immediate communication with God. For the affections are (for the most part) quick and vigorous in the youth of our profession; and their operations are sensible to those in whom they blossom, and whose fruits are visible; these make young believers seem always fresh and green in the ways of holiness. But it may be that after awhile it seems good to the sovereign Disposer of this affair, to turn the streams of grace and holiness into another channel, as it were. The Spirit sees that the exercise of humility, godly sorrow, fear, and diligent conflicting with temptations, perhaps strike at the very root of faith and love, and are more needed for them. He will therefore so order his dispensations towards these believers — by afflictions, temptations, and the occasions of life in the world — that they will have new work to do; and all the grace they have is turned into a new exercise.

On this turn, it may be that they do not find that sensible vigor in their spiritual affections, nor that delight in their spiritual duties, which they found formerly. This sometimes makes them ready to conclude that grace has decayed in them, that the springs of holiness are drying up, and they know neither where they are nor what they are. And yet, it may be, the real work of sanctification is still thriving and effectively carried on in them.

3. It is acknowledged that there may be, that there are in many, great decays in grace and holiness; that the work of sanctification goes backward in them, and that may be universally and for a long season. Many actings of grace are lost in such persons, and the things that remain are ready to die. The Scripture abundantly testifies to this, and it gives us instances of it. How often God charges his people with backsliding, barrenness, and decays in faith and love! And the experience of the days in which we live, sufficiently confirms the truth of it. Are there not open and visible decays in many as to the whole spirit of holiness, as to all its duties and fruits? Can the best among us not contribute something to evidence this from our own experience? What shall we say, then? Is there no sincere holiness where such decays are found? God forbid! But we must ask the reasons why this comes to pass, seeing that this is contrary to the gradual progress of holiness in those who are sanctified, which we asserted. I answer, two things:

(1.) That these decays are occasional and preternatural 813 as to the true nature and constitution of the new creature, and they are a disturbance of the ordinary work of grace. They are diseases in our spiritual state, which it is not to be measured by. Are you dead and cold in duties, backward in good works, careless of your heart and thoughts, addicted to the world? — these things do not belong to the state of sanctification, but are enemies to it; they are sicknesses and diseases in the spiritual constitution of the persons in whom they are found.

(2.) Although our sanctification and growth in holiness is a work of the Holy Spirit, as the efficient cause of it, yet it is also our own work, by way of duty. He has prescribed for us what our part will be, what he expects from us and requires of us, so that the work may be regularly carried on to perfection, as declared before. And there are two sorts of things which will, if we do not properly attend to them, obstruct and retard the orderly progress of holiness; for —

[1.] The power and growth of any lust or corruption, from a compliance with its temptations, is inseparable from the prevalence of any sin in us; and it lies directly against this progress. If we allow or approve of any such thing in us; if we indulge any actings of sin, especially when they are known and have grown frequent in any one kind; if we neglect the use of the best means for the constant mortification of sin — which every enlightened soul understands is necessary to this orderly progress in holiness — there is, and there will be increased, a universal decay in holiness.

And this power and growth is not only in that particular corruption which has been spared and indulged. A disease in any one of the vital organs or principal parts of the body, does not weaken only the part in which it acts, but the whole body; it vitiates814 the whole constitution by the sympathy of its parts. Indulging any particular lust, vitiates the whole of our spiritual health, and it weakens the soul in all its duties of obedience.

[2.] There are some things required of us to attain this end, that holiness may thrive and be carried on in us. These include the constant use of all ordinances and means appointed for that end; a due observance of commanded duties in their season; with a readiness to exercise every special grace in its proper circumstances. Now, if we neglect these things, if we walk at all uncertainly with God, attending neither to the means nor to our duties, nor exercising grace as we should, then we should not wonder if we find ourselves decaying and, indeed, ready to die.Rev 3.2 Does anyone wonder at seeing someone formerly of a sound constitution, who has grown weak and sickly, if he openly neglects all the means of health, and contracts all sorts of diseases by his intemperance? Is it strange that a nation should be sick and faint at heart, that grey hairs should be sprinkled upon it, that it should be poor and decaying, while consuming lusts and a neglect of all invigorating means prevail in it? It is no more strange that a professing people should decay in their holy obedience, while they abide in the neglect just described.

Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus.
~ Philippians 3:12

Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.
~ Romans 6:6

I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.
~ Romans 12:1

For this is the will of God, even your sanctification, that ye should abstain from fornication:
~ 1 Thessalonians 4:3