John the Apostle
John 17:19ESV·traditional attribution

And for their sake I consecrate myself, that they also may be sanctified in truth.

John Calvin Reformed @genevareformer

19. And for their sales I sanctify myself. By these words he explains more clearly from what source that sanctification flows, which is completed in us by the doctrine of the Gospel. It is, because he consecrated himself to the Father, that his holiness might come to us; for as the blessing on the first-fruits is spread over the whole harvest, so the Spirit of...

Matthew Henry Presbyterian @wholebiblehenry

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 (Joh 17:17): 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.

Commenting on John 17:17-19

John Gill Reformed Baptist @doctorgill

Neither pray I for these alone,.... Meaning his immediate apostles and disciples, for whose preservation and sanctification he had been particularly praying in Joh 17:19; and now, that it might not be thought that these were his only favourites, and the only persons he had a regard for, and to whom his intercession and sacrifice were confined; he adds, but for them also which shall...