“The covenant is reserved for Isaac”

The objection

“The covenant is reserved for Isaac.”

Genesis says so in so many words:

Sarah thy wife shall bear thee a son indeed; and thou shalt call his name Isaac: and I will establish my covenant with him for an everlasting covenant, and with his seed after him.

Genesis 17:19

And it says it again just after blessing Ishmael: “my covenant will I establish with Isaac” (Genesis 17:21). And in the same book, when Sarah asks for Hagar and her son to be sent away, God says to Abraham: “in Isaac shall thy seed be called” (Genesis 21:12). The covenant, everlasting, would pass through Isaac alone, and prophethood with it. Sami Ameri states the objection thus: the Torah would reserve prophethood for the sons of Isaac (Ameri, p. 147).

The answer

The covenant is first given to all the seed of Abraham

In Genesis, before the promise of Isaac, God says to Abraham, who then has only Ishmael: “Thou shalt keep my covenant therefore, thou, and thy seed after thee” (Genesis 17:9). Circumcision is its sign, “a token of the covenant” (Genesis 17:11), and Ishmael is circumcised that very day, at thirteen (Genesis 17:23-26; Ameri, p. 147-148). The next chapter, before the birth of Isaac, promises the blessing to the obedient seed of Abraham. In it, God says of him: “I know him, that he will command his children and his household after him, and they shall keep the way of the LORD” (Genesis 18:19; Ameri, p. 147-148).

Ishmael is blessed in the same passage

In Genesis, to the prayer of Abraham for Ishmael, God replies:

And as for Ishmael, I have heard thee: Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly; twelve princes shall he beget, and I will make him a great nation.

Genesis 17:20

For Munqidh al-Saqqar, the blessing of Ishmael is spoken in the same words as that of Isaac, and the text makes no distinction between the two brothers: for Isaac, one reads in it prophethood, the Book, kingship and number, and the same blessing, given to Ishmael, cannot mean less (al-Saqqar, p. 50). A blessing from God, moreover, presupposes faith: it would be strange good news for Abraham to learn that Ishmael would have a multitude of unbelieving descendants (Ameri, p. 143, 147).

In Genesis, God says, straight after the words that name Isaac: “And also of the son of the bondwoman will I make a nation, because he is thy seed” (Genesis 21:13). The text invoked against Ishmael calls him, in the same speech, the seed of Abraham.

“Everlasting” speaks of a duration, and the blessing has conditions

Munqidh al-Saqqar shows that in the Bible these words of eternity express a duration: the leprosy of Naaman shall cleave to Gehazi and to his seed “for ever” (2 Kings 5:27; al-Saqqar, p. 49). And the blessing of Israel was not unconditional: “If ye will not hear […] I will curse your blessings” (Malachi 2:2; al-Saqqar, p. 48-50).

The Law protects the firstborn

Ishmael is the firstborn of Abraham, born when his father was 86, Isaac when he was 100 (Genesis 16:16; 21:5). Yet the Law upholds the right of the firstborn, even if he is the son of the hated wife: “the right of the firstborn is his” (Deuteronomy 21:17; Ameri, p. 149).

Neither Jews nor Christians make it exclusive

Maimonides holds Job and his friends to be prophets, though they were not Israelites, and judges a prophet by his teaching, not by his lineage; Nethanel al-Fayyumi teaches that God sends prophets to every people, to the point of recognising the prophethood of Muhammad ﷺ, which he says was meant for the Arabs (Ameri, p. 150).
The argument turns against the Christians, whose religion passed from Israel to the nations. In the Gospel of Matthew, Jesus announces it himself: “The kingdom of God shall be taken from you, and given to a nation bringing forth the fruits thereof” (Matthew 21:43; Ameri, p. 150-151).

What the objection gets right

The present text does distinguish the two sons: the covenant is established with Isaac (Genesis 17:21), and the great nation is promised to Ishmael (Genesis 17:20). We do not dispute it.

But the thesis does not rest on the covenant. It rests on the blessing promised to Ishmael, in the same passage, and on the prayer of Abraham and Ishmael reported by the Qur’an (2:129). Number, blessing and strength came together among the sons of Ishmael only with the mission of Muhammad ﷺ (Ameri, p. 153). This is what the page on the prayer of Abraham shows in detail.

Sources for this page

Qur’an: Tanzil text (Uthmani); translation of the meaning by this site.
Bible: King James Version.
Sami Ameri, al-Bishara bi-nabi al-islam fi kutub al-yahud wa-l-nasara, Takween, 2nd ed., 2021, p. 143-153.
Munqidh al-Saqqar, Hal bashshara al-Kitab al-Muqaddas bi-Muhammad ﷺ?, al-Huda wa-l-Nur series, 5, 2023, p. 48-50.
Research file “Annonces du Prophète ﷺ”, v1.0, 14 October 2026, part 1.