Gen 17:6

“AND I WILL MAKE NATIONS OF THEE. The language of Rashi: “Israel and Edom are referred to here, for Ishmael was already born to him, and He could not therefore have been making any announcement concerning him.” But in my opinion it is not correct that He should inform him of Esau at the time of the covenant of circumcision since Esau does not observe circumcision and has not been commanded thereon, as the Sages expounded in Tractate Sanhedrin: “For in Isaac shall seed be called to thee, but not all of Isaac.” of the children of Isaac, namely Jacob and Esau, but only “in” Isaac, meaning only one, Jacob. Instead, [the proper interpretation is that] Israel alone is called “nations” and “peoples,” as in the verses: Yea, He loveth the peoples; They shall call peoples unto the mountains;, Verse 19. After thee, Benjamin, among the peoples. Even after the birth of all the tribes, He said: A nation and a company of nations shall be of thee; And I will make of thee a company of peoples., 48:4.”

“And I will make thee 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 thee; as the nations of Israel and Judah, of the Midianites and Edomites, of the Arabs, Saracens, and Turks: and kings shall come out of thee; 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.”