God asked Abraham to sacrifice Isaac, so why does the angel of the Lord say:

“Now I know that you fear God, because you have not withheld from ME your son, your only son.” Gen 22:12

He specifically says: “Do not lay a hand on the boy,” he said. “Do not do anything to him. Now I know that you fear God, because you have not withheld from me your son, your only son.” instead of saying now I know you do not fear ME if he goes on to say you have not withheld from ME your son.

He’s speaking as both himself and as if he’s God.

Why is this?