What does John 10:34-36 mean?

34 Jesus answered them, Is it not written in your law, I said, Ye are gods? 35 If he called them gods, unto whom the word of God came, and the scripture cannot be broken; 36 Say ye of him, whom the Father hath sanctified, and sent into the world, Thou blasphemest; because I said, I am the Son of God? (John 10:34-36 KJV)

William Burkitt’s Commentary

Here our Saviour by a two-fold argument vindicates himself from the imputation of blasphemy, in assertion himself to be God.

1. Because the Old Testament gave to magistrates and judges the title of gods, I have said ye are gods Psalms 82:6. Now Christ argues strongly from the less to the greater, thus: “If judges and magistrates may be called gods, because they are commissioned by him, and derive their authority from him, how much more is that title due to me, who was sanctified, separated, and ordained for a Mediator, and appointed to the work of redemption, before I came into the world, and consequently was God from all eternity?”

This place the Socinians (whose professed adversaries of our Saviour’s godhead) produce to prove, that Christ was not God by nature, but only in respect of his sanctification and mission. It is a certain truth, that he was not therefore the Son of God, because sanctified and sent. His sanctification was not the ground of his sonship; but his sonship was the cause of his sanctification. Christ was not therefore God’s Son, because he was sanctified and sent; but he was therefore sanctified and sent, because he was his Son. He was a Son before he was sent, even from eternity, otherwise, it must have been said, that God sent him to be his Son, and not that God sent his Son. This supposes him before he was sent out have been actually his Son, as certainly he was, from before the foundation of the world. Proverbs 8:25 I was set up from everlasting, from the beginning, or ever the world was.