The Holy Spirit, in the Word of God, receives certain names which by their very nature serve to reveal to us His Person and work. He is called the Spirit of Christ because He is given to Jesus Christ our Lord at His ascension, to be the Spirit of the Mediator. He is also called the Comforter, as the One Who comes in Christ’s name and works the comfort of salvation in the hearts of God’s elect. So also He is called in Scripture, the Spirit of Truth. 

When our Lord stood in the upper room in the night in which He was betrayed, He spoke with His disciples particularly of the coming of the Comforter which He would ask and receive of the Father and Whom the Father would send in His Name. It is also in that discourse, as it is recorded in the Gospel of John, that Jesus speaks concerning the coming Spirit as the Spirit of Truth. This word the disciples most needed to hear, for Jesus had said to them that He was going away, He Who was Himself the perfect revelation of the Father, the Word made flesh, the Way, the Truth, and the Life. Would then that Word of God, that truth as it is in Jesus Christ be taken from them and they be left comfortless? This could not be. For Jesus was going to the cross, that there the truth of God’s saving promise might be established, and mercy and truth meet together in His suffering and death, and our salvation be accomplished. Nor would our Savior leave His church without the comfort of His presence, but would Himself come in the Spirit to fill His church with all the blessings of salvation accomplished in His cross and with the truth, as it is in Jesus. Therefore in John 14:16-18our Lord speaks to His disciples of the promise of the Comforter, the Spirit of Truth which the world cannot receive, but Who should be in us, and by Whom He Himself would come to us. 

Therein lies the work of the Spirit of Christ as the Spirit of Truth. For by His Spirit, Christ Jesus our Lord gives us to know the truth, that truth as it is in Him, so that we might find in Jesus Christ all our salvation. He anoints us by His Spirit, that we might know and understand spiritual things, know His Word, discern the truth from the lie, and walk in the truth. In the light of that work of the Spirit of Truth in the believing child of God, the Scriptures speak of the office of believer. In I John 2:20, 21,

But ye have an unction from the Holy One, and ye know all things. I have not written unto you because ye know not the truth, but because ye know it, and that no lie is of the truth.

and again in I John 2:27,

But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him.

It is as the One Who both gives us to know the truth, Himself works the truth in our hearts, and keeps us in the truth, that the Spirit of Christ is given us as His people, and as such also comforts us in the truth. 

That work of the Spirit of Truth must not be conceived of in an individualistic way, however. As believers, as partakers of the Spirit of Christ, we are united by that one Spirit in the body of Christ as members of one another, having one Spirit, one Lord, and one faith. When our Lord set before His disciples in the upper room the promise of the Spirit of Truth, He was addressing not a mere group of individual believers, but the apostles, by whom and through whom He would lay the foundation of the New Testament church. It was to the church, as the body of Christ as it is now manifested in the church institute, that Christ gave the promise of the Spirit of Truth; and it was also upon that church that He poured out His Spirit in fulfillment of that promise. 

By that Spirit in the church Christ would give His truth unto His people in objective form in the written Word of God and lay the foundation of His church. The apostles needed to hear this that night in the upper room. Jesus would not now cease to teach them, but, on the contrary, when the Comforter Who would be sent in Christ’s Name would come, He would teach them all things and bring to remembrance whatsoever Jesus had said (John 14:26). Moreover, by the power of that Spirit of Truth in them, they would also preach that Word (John 15:26, 27), and the Spirit Himself would testify of Christ by it, reproving the world of sin, and of righteousness and of judgment (John 16:7-11). Thus we read in John 16:12-14:

I have yet many things to say unto you, but ye cannot bear them now. Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. He shall glorify me: for he shall receive of mine, and shall shew it unto you.

By that work of the Spirit of Truth we as the church of Christ received the New Testament Scriptures. In like manner also the Spirit of Christ spoke through the prophets in the Old Testament (II Peter 1:20, 21). That Word of God is not the work of man but the work of the Spirit of Truth, Christ’s Word to His church, the objective foundation of the truth and our faith. By that work of the Spirit we have received the Word of Truth, the Word of God. 

That same Spirit of Truth also abides in the church and works in the church to guide her into all the truth of that Word. Through the working of the Spirit in the church in the communion of saints and under the preaching of the Word, we are led to lay hold of that Word of truth and to appropriate the truth of Jesus Christ. The same Spirit Who gave that Word also works by that Word in the hearts of God’s people, convicting us of sin and calling us unto faith and the knowledge of the truth. 

The result is that we grow in the knowledge of the truth. This is true moreover, not only for us as individuals, but also for the church of Christ. Under the leading of the Spirit of Truth, the church of Jesus Christ is led to develop the truth of the Word of God, to elicit from the Scriptures in ever richer form the doctrines contained in them. Fundamentally the church always possesses that truth, for she possesses Christ in Whom that truth lies centrally. But under the leading of the Spirit she grows in that truth, perceives it more clearly, holds it more richly and develops in an understanding of that truth for all her faith and life. 

This work of the Spirit of Truth is an organic work in the life of the church, by which, in the generations of God’s people, the church is guided into all the riches which she possesses in Jesus Christ. Each generation builds upon the heritage of the truth which they have received from those who have gone before, enriching that heritage and passing it on to those who follow. By this work of the Spirit of Truth the church is given to confess the truth in the creeds and confessions of the church and to build upon it. Such growth and development is not the result of the leading by the Spirit of simply any one individual, but His leading of the church, as she stands as the body of Christ in the midst of the world. 

To accomplish this work the Spirit uses the growth and development of believers as they stand together in the bond of faith and as they are called to confess that faith together, to contend for the truth over against the lie, and to live out of that truth in the midst of the world. Nor does the truth always develop in a straight path. For heresies have arisen and will continue to arise in the church, which would corrupt the church’s heritage and ultimately destroy it. As a result, the people of God are driven to the Word to defend that truth. Thus in God’s Providence, heresy also must serve the Spirit of Truth in the church by driving the church to explore the truth and its riches more thoroughly and to confess it more clearly. The church institute itself may become corrupt and depart from the truth. It may even do so while claiming to be led by the Spirit, though departing from the Word of God, the Word of truth. But by the Spirit of Truth, God not only keeps His church in history, but also reforms it, and if need be founds it anew by way of reformation and renewal in the truth. For even as the church develops in the truth, so also, alongside it, the lie and the assault of the lie develop. For the false church always develops at the side of the true church of Christ, and indeed from within it. That church therefore which would remain true to God’s Word must ever contend for that faith once delivered to the saints by the Spirit of Truth. This too is the work not simply of believers alone, but of Christ, Who by His Spirit keeps His people in the truth and preserves also His church and His truth by His Spirit and Word, and by the exercise of the keys of the kingdom. 

In that warfare the church shall stand victorious in truth, for Christ keeps His church by His Spirit and guides her ever into all truth. He it is Who has promised, “I will not leave you comfortless: I will come to you” (John 14:18).