Some will have the meaning to be, that Christ was before Abraham's time constituted Mediator; as he is said to be the Lamb slain from the foundation of the world, Revelation 13:8: so 1 Peter 1:20. But thus it might have been said of any of the elect, that they were chosen before Abraham was. It is therefore undoubtedly to be understood of Christ's eternal existence, as to his Divine nature; and this will appear, as from other arguments, so from the whole scope of our Saviour's former discourse in this chapter, which was to assert his Divine nature and equality with the Father.
Related Commentaries of John 8:58
John 8:58
58 Jesus said unto them,Verily, verily, I say unto you, Before Abraham was, I am.