The angel of the Lord, i.e. Christ the Angel of the covenant, as appears from Genesis 22:12,16. He repeats his name to prevent Abraham, whom he knew to be most expeditious in God's service, and just ready to give the deadly blow.
Related Commentaries of Genesis 22:11
Genesis 22:11
11 And the angel of the LORD called unto him out of heaven, and said, Abraham, Abraham: and he said, Here am I.