William Burkitt on John 17:12

Observe, here, 1. That those which shall be saved, are given unto Christ, and committed to his care and trust.

2. That none of those that are given unto Christ, as his charge, and committed to his care and trust, shall be finally lost: Those that thou gavest me I have kept, and none of them is lost: it follows, but the Son of perdition.

A person may be said to be the son of perdition two ways; actively and passively.

Actively, he is so who makes it his work and business to destroy others.

Passively, he is a son of perdition, who for his wickedness in destroying others, is destroyed himself.

Judas was a son of perdition in both these senses; his heart was maliciously set upon destroying Christ, and willfully set upon his own destruction: his coveteousness and hypocrisy prompted him to betray our Saviour, his despair provoked him to destroy himself.