While I was with them— "During my personal abode with them, I kept them in the firm faith, and in thesteadfast practice of the precepts of my holy religion, so far as I revealed those unto them. I say the twelve men whom thou gavest me for apostles I have thus kept, insomuch that none of them have apostatized, but Judas Iscariot, that wicked person, who deserves perdition; and therefore it was long ago predicted in the scriptures, particularly in Psalms 109:8." See on ch. John 13:19. As the phrase, son of death, 1 Samuel 26:16. [Margin,] signifies one who deserves death; and a child of hell, Matthew 23:15 signifies one who deserves hell; so here son of perdition, signifies a person who deserves perdition.
Related Commentaries of John 17:12
John 17:12
12 While I was with them in the world, I kept them in thy name: those that thou gavest me I have kept, and none of them is lost, but the son of perdition; that the scripture might be fulfilled.