John Gill Commentary Genesis 17:4

"As for me, behold, my covenant is with thee, and thou shalt be the father of a multitude of nations." — Genesis 17:4 (ASV)

As for me, behold, my covenant [is] with you Who was gracious to make it, faithful to keep it, and immutable in it, though Abram was but a man, and sinful:

and you shall be a father of many nations : as he was of many Arabian nations, and of the Turks in the line of Ishmael; and of the Midianites, and others, in the line of his sons by Keturah; and of the Israelites in the line of Isaac, as well as of the Edomites in the line of Esau; and in a spiritual sense the father of all that believe, in all the nations of the world, circumcised or uncircumcised, as the apostle explains it, (Romans 4:11Romans 4:12Romans 4:16–18) .