John 17:12 - Matthew Poole's English Annotations on the Holy Bible

Christ speaks here of himself as one who had already died, was risen, and ascended, though none of all these things were past, because they were so suddenly to come to pass. I have, (saith our Saviour), for all the time that I have abode in the world, and conversed with them, kept them in thy name, i.e. in the steady owning and profession of thy truth; or (if we read it, through thy name) it signifieth through thy power, and the influence of thy grace. I have not so kept all that came to hear me, but all those whom thou gavest me by the act of thy eternal counsel; or whom thou gavest me to be my apostles: and none of them is proved an apostate, but the son of perdition: none of them is lost whom thou gavest me by thy eternal gift, none of them whom thou gavest me to be my apostles, but one who, though he was my apostle, and in that sense given to me, yet was never given me by thy eternal gift, as one to be by me redeemed, and brought to eternal life and salvation; for he was a son of perdition: we have this term applied to antichrist, 2 Thessalonians 2:3. As the son of death, 2 Samuel 12:5, signifies one appointed to die, or that deserveth to die; and the child of hell, Matthew 23:15, signifieth one who deserveth hell; so the son of perdition may either signify one destined to perdition, or one that walketh in the high and right road to perdition, or rather both; one who being passed over in God's eternal counsels, as to such as shall be saved, hath by his own wilful apostasy brought himself to eternal perdition, or into such a guilt as I know thou wilt destroy him. And by this the Holy Scripture is fulfilled, Psalms 109:8, for that is the portion of Scripture here intended, as is apparent from Acts 1:20, where the apostle applies that text to Judas, who is here spoken of. Other scriptures also were thus fulfilled, as Psalms 41:9, compared with 1 Thessalonians 13:18.