John Gill Commentary Genesis 17:6

"And I will make thee exceeding fruitful, and I will make nations of thee, and kings shall come out of thee." — Genesis 17:6 (ASV)

And I will make you exceeding fruitful
In children, for he had not only a son by Sarai, from whom sprung a numerous offspring, but he had six sons by Keturah, who became the heads of large nations:

and I will make nations of you ;
as the nations of Israel and Judah, of the Midianites and Edomites, of the Arabs, Saracens, and Turks:

and kings shall come out of you ;
as the twelve princes of Ishmael, the kings of Edom and Midian, of the Arabs, Saracens, and Turks, and of Israel and Judah, and especially, as observed by Grotius, and others, the King Messiah: to which may be added, in a mystical sense, all Christian kings and princes of the same faith with him; nay, all believers, who are all kings and priests unto God.