Albert Barnes Commentary John 11:51

"Now this he said not of himself: but, being high priest that year, he prophesied that Jesus should die for the nation;" — John 11:51 (ASV)

Not of himself. Though he uttered what proved to be a true prophecy, it was accomplished in a way that he did not intend. He had a wicked design; he was plotting murder and crime. Yet, wicked as he was, and little as he intended it, God so ordered it that he delivered a most precious truth respecting the atonement. Remark,

1. God may fulfill the words of the wicked in a manner that they do not wish or intend.
2. He may make even their malice and wicked plots the very means of accomplishing His purposes. What they regard as the fulfillment of their plans, God may make the fulfillment of His, yet so as directly to overthrow their designs and prostrate them in ruin.
3. Sinners should tremble and be afraid when they lay plans against God or seek to treat others unjustly.

Being high-priest that year. It is not to be supposed that Caiaphas was a true prophet, or was conscious of the meaning John has ascribed to his words. However, his words express the truth about the atonement of Jesus, and John records it as a remarkable circumstance that the high-priest of the nation should unwittingly utter a statement that turned out to be the truth about the death of Jesus.

Great importance was attached to the opinion of the high-priest by the Jews, because it was by him that the judgment by Urim and Thummim was formerly declared in cases of importance and difficulty (Numbers 27:21).

It is not certain or probable that the high-priest was ever endowed with the gift of prophecy. Nevertheless, he held a high office, the authority of his name was great, and it was hence remarkable that he uttered a declaration which the result showed to be true, though not in the sense that he intended.

He prophesied. He uttered words that proved to be prophetic, or he expressed at that time a statement that turned out to be true. It does not mean that he was inspired, or that he deserved to be ranked among the true prophets; but his words were such that they accurately expressed a future event. The word prophecy is to be taken here not in the strict sense, but in a sense that is not uncommon in the sacred writers (Acts 21:9: And the same man had four daughters, virgins, which did prophesy. See notes on Revelation 12:6. For comparison, see also notes on 1 Corinthians 14:1. Additionally, see notes on Matthew 26:68 and Luke 22:64).

That Jesus should die. Die in the place of men, or as an atonement for sinners. This is evidently the meaning that John attaches to the words.

For that nation. For the Jews. As a sacrifice for their sins. In no other sense whatever could it be said that he died for them. His death, so far from saving them in the sense in which the high-priest understood it, was the very occasion of their destruction. They invoked the vengeance of God when they said, His blood be on us and on our children (Matthew 27:25), and all these calamities came upon them because they would not come to him and be saved—that is, because they rejected him and put him to death (Matthew 23:37–39).