New Defender's Study Bible Notes
17:17 Sanctify them. The process of sanctification (that is, of being set apart from this world for His service) is accomplished through the Word of God (Ephesians 5:26), by “the Spirit and belief of the truth” (II Thessalonians 2:13).
17:18 sent them. Jesus frequently spoke of being sent into the world by His Father (e.g., John 10:36). He was sent for one main purpose—“that the world through Him might be saved” (John 3:17). In the same way, and for the same purpose, His disciples are now sent into the world (John 20:21).