What does John 8:57-59 mean?

57 Then said the Jews unto him, Thou art not yet fifty years old, and hast thou seen Abraham? 58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am. 59 Then took they up stones to cast at him: but Jesus hid himself, and went out of the temple, going through the midst of them, and so passed by. (John 8:57-59 KJV)

William Burkitt’s Commentary

Observe here, 1. What a false and ridiculous construction the Jews make of our Saviour’s words, as if he had affirmed that he had seen Abraham, and Abraham him, with bodily eyes: whereas Christ only asserted, that Abraham had seen his day: that is, he foresaw by faith the day of his incarnation, and coming in the flesh.

Observe, 2. Our Saviour’s positive asserting of his divinity, or that he had a being as God from all eternity: for, says he, Before Abraham was, I am.

Where note, That Christ does not say, Before Abraham was, I was: but, before Abraham was, I am; which is the proper name of God, thereby is signified the eternal duration and permanency of his being. The adversaries of Christ’s divinity say, that before Abraham was, Christ was: that is, in God’s fore-knowledge or decree; but this may be said of any other person as well as Chirst, that he was in the fore-knowledge of God before Abraham was born. Whereas undoubtedly it was Christ’s design in these words, to give himself some preference and advantage above Abraham, which this interpretation doth not in the least do.

Observe lastly, how the Jews looking upon Christ as a blasphemer, for making himself equal with God, and for asserting his eternal existence, they make a furious attempt upon his life, by taking up stones to cast at him, as the Jews used to deal with blasphemers: but our Saviour delivers himself miraculously from their fury, and escapes untouched.

Hence learn, That when arguments fail, the enemies of truth betake themselves to force and violence: They took up stones to cast at him.

2. That as Christ disappointed his own persecutors, so he can and will deliver his people in their greatest extremity from their persecutor’s rage and fury. The Lord knoweth how to deliver the godly out of temptation, and to reserve the unjust to the day of judgment to be punished. 2 Peter 2:9