John Chrysostom

(Hom. lxxxii) Or thus: Sanctify them in Thy truth; i. e. Make them holy, by the gift of the Holy Spirit, and sound doctrines: for sound doctrines give knowledge of God, and sanctify the soul. And as He is speaking of doctrines, He adds, Thy word is truth, i. e. there is in it no lie, nor any thing typical, or bodily. Again, Sanctify them in Thy truth, may mean, Separate them for the ministry of the word, and preaching.