I believe He was talking about Himself. In other words, He existed before Abraham existed (John-1:1) At that moment, the Jewish people and the rabbi's should have known that He was the Messiah. He said: IAM-This is the same IAM that Moses heard of; this was, also, there clue.
I and my Father are one. Meaning, I AM your God. As He said so many times, if your see me, you have seen my Father, for He and I are one. He is, also, the bread of life. His body was given to us Tru Calvary, so if you believe that this sacrifice in the cross was for your sins,than you would be safe. Surely He was beating for our transgressions and by His stripes we are heal. We, as Christian came to be, because, of Christ and with out Him we are nothing and we would NOT have a name. Jesus is the vine, we are the branches. He hold us together and without Him, we parish. He will always survive,exist,be. We, with out Him will die. (also, eternal). He says: IAM the truth and life- He, being THE GOD, is the way of our salvation. God, the Father, sent His Son, Jesus as the Lamb to be kill as the only acceptable sacrifice, so, we can have eternal life and as He, Jesus walked out of the grave, we can, also, be resurrected for life in eternity.
Father, Son and Holy Spirit. ONE GOD.