John 17:17

Sanctify them in thy truth; thy word is truth.

As Reynolds noted:

A long controversy has prevailed in the church as to whether the Spirit's gracious operations are or are not limited by the operation of truth on the mind. Numerous assurances of the New Testament seem thus to limit the grace of God, or to measure it by the ordinary effect produced on the understanding by divine truth.[18]

Reynolds disagreed that such a "limitation" exists, but he was correct in his mention of "numerous assurances" of the New Testament which prove that it does exist. The proximity of this teaching of Jesus to his promise of the Holy Spirit who would guide them into all truth, together with the specific mention here of the truth as the instrument, or means, of their sanctification positively shows that whatever the Spirit accomplishes the means of it is sacred truth itself.

Regarding alien sinners, it is certain that the only power capable of producing faith in them is the word of God. As J. D. Thomas said:

We insist that the only power used to produce faith in the alien sinner is the word of God. Although denominationalists are slow to see this (perhaps due to inherited Calvinism), the teaching of the New Testament is very clear about the place of the gospel in producing faith. "The gospel is the power unto salvation" (Romans 1:16), and "faith comes by hearing the word" (Romans 10:17).[19]

Regarding the work of the Spirit in the hearts of Christians, however, the above limitation does not seem to be so complete. Again from Thomas:

The Spirit is not the word and is not limited to the use of the written word in all that he does (for instance, help our weakness, or intercede). "The Spirit also helps our weaknesses; for we know not how to pray as we should, but the Spirit himself intercedes for us with groanings too deep for words" (Romans 8:26).[20]

Despite the exceptions cited by Thomas, Jesus here clearly indicated that the divine truth would sanctify the apostles themselves, and this is grounds enough for denying that the Holy Spirit sanctifies Christians in some manner different from that. Perhaps a part of the difficulty lies in the failure to recognize the word itself as a living and abiding entity in the soul of the believer. "Let the word of Christ dwell in you richly" (Colossians 3:16) is exactly the equivalent of the Holy Spirit's indwelling; and many of the things said to be done by the Spirit are also said to be done by the word of God. It is not the purpose here to thresh all of the old arguments pro and con on this question; but we shall venture one dogmatic conclusion, namely, that the Holy Spirit never performs any kind of work in the human soul that is contrary to, or out of harmony with, the Scriptures. The notion, and it is merely that, of the Spirit's entering the soul and making it independent of the word of God, is not found in the Scriptures. There are no instances, not even in the case of the apostles, of persons going on unto a more perfect state of sanctification without the constant necessity of their remaining under the tutelage of the revealed will of God; and that seems to be the very point of this verse.

Thy word is truth ... is but another way of saying the Bible is truth. It is uniquely the word of God.

[18] H. R. Reynolds. The Pulpit Commentary (Grand Rapids, Michigan: William B. Eerdmans Publishing Company, 1962), II, p. 349.

[19] J. D. Thomas, The Spirit and Spirituality (Abilene, Texas: Biblical Research Press, 1966), p. 10.

[20] Ibid., p. 15.