Charles Ellicott Commentary John 17:19

"And for their sakes I sanctify myself, that they themselves also may be sanctified in truth." — John 17:19 (ASV)

And for their sakes I sanctify myself.—Compare Note on John 17:17. The consecration here thought of is that to the work which was immediately before Him—the offering Himself as a sacrifice. The word was in frequent use in the special sense of an offering or sacrifice set apart to God. As a New Testament example of this, compare Romans 15:16. By this consecration of Himself—which in a wider sense is for all people, but in the special sense is “for their sakes”—He will, as both Priest and Sacrifice, enter into the Holy of Holies of the heavenly temple, and will send the Holy Ghost, who will consecrate them.

That they also might be sanctified through the truth.—Better, as in the margin, . . . . might be truly sanctified. The words “they also” are emphatic, corresponding to “their sakes” and “myself” in the preceding clause.