Abraham knew Jesus Christ

The declaration of Jesus about Abraham disqualifies any Angel  as a plausible Jesus in heaven

Your father Abraham leaped for joy that he should see My day, and he saw, and rejoiced.  (John 8:56 LITV)

Jesus said to them, Truly, truly, I say to you, Before Abraham came to be, I AM!  (John 8:58 LITV)

Who was the God of Abraham’s, the Father of the Jews? An Angel?

Angel of Jehovah interacted very closely with Abraham as if He is Yahweh himself (Exodus 23:23). But the God of Abraham is El-Shaddai (Genesis 17:1) who was later revealed to Moses as Yahweh, the God of Abraham, Isaac, and Jacob. Abraham called Him Adonai. The statement of John 8:56 clearly denotes that Abraham saw the day of Jesus when He was known as El-Shaddai (Adonai) who took the name Jehovah with Moses until the end of times. Therefore, John 8:56 is one the verses where Jesus reveals His true identity in heaven and which implies that none of the Angels could have been Jesus.