Apart from the few introductory words, John 17. is a chapter of prayer, and from what precede and follow the words, "Sanctify them in the truth," it is evident that the Lord Jesus was intensely concerned about His Apostles when they would be left in the world without Himself to lead and guide them. If in Nazareth's synagogue His words of grace caused all there to wonder, what must the Apostles have thought as they listened to Him praying to His Father regarding themselves! They had been given to Him by the Father; He had kept them, and guarded them, and had manifested His Father's Name to them; and they had received the words given Him by His Father, from Whom they knew He had been sent.
Remembering all that had been spoken, the Lord says, "I have given them Thy word." Now, in view of His prospective absence, His prayer is that they should be kept from the Evil One. "They are not of the world," He says, "even as I am not of the world. Sanctify them in the truth: Thy word is truth."
"Sanctify" here (verse 17) conveys the idea of being set apart, or separated, for a divine purpose. We may think of it as if the Truth-the Word of God-is all around the disciples; that whichever way they move, the truth of God is there to regulate and guide in all things, so they may conform to it. The Lord Jesus as the Great Example sanctified Himself in order that disciples should likewise be set apart, and that in truth. Being thus set apart, the disciple becomes separated to God indeed; and the truth (whether thought of as to specific sayings of the Lord Jesus, or as one whole-the word come from God), reminds him that while in the world he ought not to be of it.
One feature of the Lord's prayer is that His joy might be found in the disciples, and this is worthy of special notice. Therefore, with this sanctification, this setting apart, this separation, there is peace and happiness consistent with truth. To assume that the path of separation is fraught with the opposite, is to have an erroneous conception of the competency of the truth of God; for in His Advocacy the words of the Lord Jesus live in the Father's ears-"Sanctify them in the truth."