By myself have I sworn: so the Lord swears by his name, Jeremiah 44:26; by his soul, in the Hebrew text, Jeremiah 51:14; by his holiness, Amos 4:2; which is the same with by himself here. Hence also it appears that the Angel who speaks here is Christ and God, because this is God's prerogative to swear by himself, as appears from Hebrews 6:13. Because thou hast done this thing; not that Abraham by this act did properly merit or purchase the following promises, as plainly appears, because the same things for substance had been freely promised to Abraham long before this time and action, Genesis 12:2, Genesis 13:16, only what before was promised is now confirmed by an oath, as a testimony of that singular respect which God had to Abraham, and to this heroical instance of faith and obedience.
Related Commentaries of Genesis 22:16
Genesis 22:16
16 And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only son: