The Joy of Jesus is all about The Truth

Christ's Intercessory Prayer.
17 Sanctify them through thy truth: thy word is truth. 18 As thou hast sent me into the world, even so have I also sent them into the world. 19 And for their sakes I sanctify myself, that they also might be sanctified through the truth.
The next thing he prayed for for them was that they might be sanctified; not only kept from evil, but made good.
I. Here is the petition (v. 17): Sanctify them through thy truth, through thy word, for thy word is truth; it is true—it is truth itself. He desires they may be sanctified,
1. As Christians. Father, make them holy, and this will be their preservation, 1 Thess. v. 23. Observe here,
(1.) The grace desired—sanctification. The disciples were sanctified, for they were not of the world; yet he prays, Father sanctify them, that is, [1.] "Confirm the work of sanctification in them, strengthen their faith, inflame their good affections, rivet their good resolutions." [2.] "Carry on that good work in them, and continue it; let the light shine more and more." [3.] "Complete it, crown it with the perfection of holiness; sanctify them throughout and to the end." Note, First, It is the prayer of Christ for all that are his that they may be sanctified; because he cannot for shame own them as his, either here or hereafter, either employ them in his work or present them to his Father, if they be not sanctified. Secondly, Those that through grace are sanctified have need to be sanctified more and more. Even disciples must pray for sanctifying grace; for, if he that was the author of the good work be not the finisher of it, we are undone. Not to go forward is to go backward; he that is holy must be holy still, more holy still, pressing forward, soaring upward, as those that have not attained. Thirdly, It is God that sanctifies as well as God that justified, 2 Cor. v. 5. Fourthly, It is an encouragement to us, in our prayers for sanctifying grace, that it is what Christ intercedes for for us.
(2.) The means of conferring this grace—through thy truth, thy word is truth. Not that the Holy One of Israel is hereby limited to means, but in the counsel of peace among other things it was settled and agreed, [1.] That all needful truth should be comprised and summed up in the word of God. Divine revelation, as it now stands in the written word, is not only pure truth without mixture, but entire truth without deficiency. [2.] That this word of truth should be the outward and ordinary means of our sanctification; not of itself, for then it would always sanctify, but as the instrument which the Spirit commonly uses in beginning and carrying on that good work; it is the seed of the new birth (1 Pet. i. 23), and the food of the new life, 1 Pet. ii. 1-2.