The Trinity

For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. For in him dwelleth all the fulness of the Godhead bodily. And ye are complete in him, which is the head of all principality and power: In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: For it pleased the Father that in him should all fulness dwell; Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ: According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love: Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will, To the praise of the glory of his grace, wherein he hath made us accepted in the beloved. In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace; That we should be to the praise of his glory, who first trusted in Christ. In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.
~ 1 John 5:7, Colossians 2:9-11, Colossians 1:19, Ephesians 1:3-7 and 12-14,

And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth. To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation. At that day ye shall know that I am in my Father, and ye in me, and I in you. That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
~ John 1:14, 2 Corinthians 5:19, John 14:20, John 17:21

Of The Trinity and a Christian, by John Bunyan.

How a young or shaken Christian should demean himself under the weighty thoughts of the Doctrine of the Trinity or Plurality of Persons in the eternal Godhead.

The reason why I say a young or shaken Christian, is, because some that are not young, but of an ancient standing, may not only be assaulted with violent temptations concerning gospel-principles, but a second time may become a child, a babe, a shallow man, in the things of God: especially, either when by backsliding he hath provoked God to leave him, or when some new, unexpected, and (as to present strength) over weighty objection doth fall upon the spirit, by means of which great shakings of mind do commonly attend such a soul in the most weighty matters of the concerns of faith, of which this is one that I have supposed in the above-mentioned question: Wherefore passing other things, I will come directly to that, and briefly propose some helps to a soul in such a case.

I. The first preparative.

First, Then, be sure thou keep close to the Word of God for that is the revelation of the mind and will of God, both as to the truth of what is either in himself or ways, and also as to what he requireth and expecteth of thee, either concerning faith in, or obedience to, what he hath so revealed. Now for thy better performing of this, I shall give thee in brief these following directions.

1. Suffer thyself, by the authority of the Word, to be persuaded that the Scripture indeed is the Word of God the Scriptures of truth, the words of the Holy One; and that they therefore must be every one true, pure, and for ever settled in heaven.

2. Conclude therefore from the former doctrine, that that God whose words they are, is able to make a reconciliation and most sweet and harmonious agreement with all the sayings therein, how obscure, cross, dark, and contradictory soever they seem to thee. To understand all mysteries, to have all knowledge, to be able to comprehend with all saints, is a great work; enough to crush the spirit, and to stretch the strings of the most capacious, widened soul that breatheth on this side glory, be they notwithstanding exceedingly enlarged by revelation. Paul, when he was caught up to heaven, saw that which was unlawful, because impossible, for man to utter. And saith Christ to the reasoning Pharisee, “If I have told you earthly things, and ye believe not, how shall you believe if I tell you of heavenly things?” It is great lewdness, and also insufferable arrogancy, to come to the Word of God, as conceiting already that whatever thou readest must either by thee be understood, or of itself fall to the ground as a senseless error. But God is wiser than man, wherefore fear thou him, and tremble at his word, saying still, with godly suspicion of thine own infirmity, What I see not, teach thou me; and, Thou art God only wise; but as for me, I am as a beast before thee.

3. Take heed of taking a part of the Word only, lest thou thereby go away with the truth as mangled in pieces. For instance, where thou readest, “The Lord our God is one Lord,” there take heed that thou dost not thence conclude, then there are not three persons in the Godhead: when thou readest of “the Father, the Son, and the Holy Spirit,” then take heed of concluding there must therefore either be three Gods, or else that Jesus Christ and the Holy Ghost are not true God, but the Father only. Wherefore to help thee here, observe,

II. The second preparative.

1. That the Christian religion requireth credit concerning every doctrine contained in the Word; credit, I say, according to the true relation of every sentence that the Holy Ghost hath revealed for the asserting, maintaining, or vindicating that same truth.

2. And therefore, hence it is that a Christian is not called a doer, a reasoner, an objector, and perverse disputer, but a believer. Be thou an example to “the believers;” and, “believers” were “added to the church,” &c.

3. Therefore, know again, that the Word, if it saith and expresseth that this or that is so and so, as to the matter in hand, thou art bound and obliged, both by the name, profession, and the truth, unto which thou hast joined thyself, to assent to, confess, and acknowledge the same, even then when thy carnal reason will not stoop thereto. “Righteous art thou, O God,” saith Jeremiah, “yet let me plead with thee; Wherefore do the wicked live?” Mark, first he acknowledgeth that God’s way with the wicked is just and right, even then when yet he could not see the reason of his actions and dispensations towards them. The same reason is good as to our present case: and hence it is that the apostle saith, the spiritual armour of Christians should be much exercised against those high towering and self-exalting imaginations, that within our own bosoms do exalt themselves against the knowledge of God; that every thought or carnal reasoning may be not only taken, but brought a captive into obedience to Christ; that is, be made to stoop to the Word of God, and to give way and place to the doctrine therein contained, how cross soever our thoughts and the Word lie to each other. And it is observable that he here saith, “they exalt themselves against the knowledge of God;” which cannot be understood, that our carnal, natural reason doth exalt itself against an eternal deity, simply considered; for that nature itself doth gather from the very things that are made, even his eternal power and Godhead: it must be then that they exalt themselves against that God as thus and thus revealed in the Word, to wit, against the knowledge of one God, consisting of three persons, Father, Son, and Spirit; for this is the doctrine of the Scriptures of truth: and therefore it is observable these thoughts must be brought captive, and be made subject in particular to the Lord Jesus Christ, as to the second person in the Godhead: for the Father is ever acknowledged by all that profess the least of religion; but the Son is that stumbling-stone and rock of offence, against which thousands dash themselves in pieces; though in him are hid all the treasures of wisdom and knowledge, and in him dwells the fulness of the Godhead bodily.