The story of Abraham's sacrifice is one of the clearest places where the Bible and the Qur'an tell related events with an important difference. Genesis names Isaac as the son whom Abraham is commanded to offer. The Qur'an does not name the son in the sacrifice passage, but its sequence places the sacrifice before the announcement of Isaac's birth. Muslims have therefore traditionally understood the son to be Ishmael.
One argument for this reading does not begin with later theology or external historical evidence. It begins with Genesis's own chronology. The argument is not, by itself, a complete proof of Islam. But it is a serious internal difficulty for identifying the sacrificed son as Isaac, and it fits the Qur'anic sequence naturally.
The chronological argument from Genesis
Genesis gives Abraham's age at the births of his two sons. When Ishmael was born, Abraham was eighty-six:
"Abram was eighty-six years old when Hagar bore Ishmael to Abram." (Genesis 16:16)
Isaac was born later, when Abraham was one hundred:
"Abraham was a hundred years old when his son Isaac was born to him." (Genesis 21:5)
On Genesis's own numbers, then, Ishmael was Abraham's only son for approximately fourteen years. Isaac was never Abraham's only son. From the moment Isaac was born, Abraham had two sons, even if one was later sent away.
Yet when God commands the sacrifice in Genesis 22:2, the wording is:
"Take your son, your only son, whom you love - Isaac - and go to the land of Moriah. Sacrifice him there as a burnt offering on a mountain that I will show you." (Genesis 22:2)
The point made by Muslim proponents is straightforward: if "your only son" is read in its ordinary numerical sense, the description fits Ishmael during the fourteen-year period before Isaac's birth. It does not fit Isaac at any point in the chronology supplied by Genesis. This is especially striking because the command is not merely to sacrifice "your son," but "your only son."
The Qur'an's narrative sequence appears to avoid this difficulty. Abraham first asks God for a righteous child. He is given good news of a forbearing boy. When the boy grows old enough to work alongside his father, Abraham sees in a dream that he must sacrifice him. The sacrifice is then ransomed, and only afterward comes the announcement of Isaac.
"My Lord, grant me a righteous child. So We gave him good news of a forbearing boy. Then, when the boy reached the age to work with him, he said, 'My dear son, I have seen in a dream that I must sacrifice you, so consider what you think.' He said, 'My dear father, do as you are commanded. You will find me, if Allah wills, among the steadfast.' ... And We ransomed him with a great sacrifice. And We left for him favourable mention among later generations: 'Peace be upon Abraham.' ... And We gave him good news of Isaac, a prophet, one of the righteous." (Qur'an 37:100-112)
Read in this order, the son of the sacrifice is the first son mentioned, while Isaac is announced afterward. This is why the majority of Muslim scholars have identified the sacrificed son as Ishmael, although the Qur'an does not explicitly insert the name Ishmael into the sacrifice verses themselves.
The strongest case for identifying Isaac as the son
A fair discussion must acknowledge that the Genesis text itself gives a substantial reply. Genesis 22:2 does not end with the words "your only son." It continues, "whom you love - Isaac." On a plain reading of the completed verse, the author identifies the intended son as Isaac. A Christian or Jewish reader may therefore say that the word "only" cannot overturn the explicit name that follows it.
There is also a contextual explanation. By the time of Genesis 22, Ishmael and his mother Hagar had been sent away in Genesis 21. Genesis says that Abraham gave Hagar bread and water, and that she and Ishmael departed into the wilderness. A defender of the Isaac interpretation may argue that Isaac was then Abraham's only son within the household, or the only son through whom the covenant promise was to continue.
Furthermore, the Hebrew word translated "only" is yahid. It can carry the sense of unique, precious, or beloved, not necessarily the strict mathematical sense of a person's sole child in every circumstance. Genesis itself calls Isaac the uniquely significant son because the covenant line is associated with him. Genesis 21:12 says, "through Isaac shall your offspring be named." On this reading, "your only son, whom you love" means your unique or specially beloved son, rather than "the only male child you have ever fathered."
These are not frivolous objections. They explain why the Jewish and Christian reading of Isaac has been deeply established in their traditions, and why the chronological argument should not be presented as though Genesis contains no answer at all.
Why that reply does not remove the difficulty
The reply, however, has its own weaknesses. First, the question is not whether Isaac was uniquely important to the covenant. The question is why Genesis uses the phrase "your only son" when its own preceding chapters have already stated that Abraham fathered Ishmael. If "only" means "unique" or "covenantally special," that is a possible interpretation, but it is not the most immediate numerical meaning.
Second, the explanation that Ishmael no longer counted because he had been sent away is not stated in Genesis 22 itself. Ishmael had not died. He remained Abraham's son, and Genesis 21 portrays Abraham grieving deeply over his departure. Calling Isaac the only son in the household may explain the phrase from one perspective, but it requires a contextual qualification that the wording does not provide.
Third, the explicit naming of Isaac creates a problem for the chronological argument, but it also creates a problem for the opposing interpretation of Genesis. A Muslim response is that the name "Isaac" may reflect a later identification or editorial presentation of the story, while the description "only son" preserves an older feature that fits Ishmael. That is a possible critical explanation, but it is not something that can be demonstrated merely from these four verses. It should therefore be offered cautiously, not as an established historical fact.
Most importantly, the Qur'an does not simply replace one name with another. Its sequence gives a coherent narrative reason for identifying the son as Ishmael: the sacrifice account occurs before the separate glad tidings of Isaac. The passage also calls the first boy "forbearing," an adjective that is often associated by Muslim exegetes with Ishmael, while Isaac is later described with the distinct good news of a prophet.
What the argument does and does not establish
The argument establishes a genuine internal tension in the Isaac reading of Genesis. If "only son" means the sole son Abraham had at the time, Genesis's ages point to Ishmael, not Isaac. Isaac was never an only son according to the chronology given. The Qur'an's arrangement of the events is also naturally consistent with Ishmael: the sacrifice comes first, and the announcement of Isaac follows afterward.
It does not establish, by chronology alone, that every reader must accept the Islamic interpretation. Genesis 22 explicitly names Isaac, and its defenders can appeal to the meanings "unique," "beloved," or "only son of the covenant," as well as to Ishmael's departure from Abraham's household. Those replies are interpretive possibilities, not something to dismiss casually.
Nor does the Qur'an's ordering function as a mathematical proof independent of interpretation. The Qur'an never says in the sacrifice verses, "the son was Ishmael." The Muslim conclusion arises from the passage's sequence, the distinction between the two announcements, the description of the first son, and the wider biblical chronology. It is a cumulative case rather than a single conclusive phrase.
Nevertheless, the cumulative case is significant. The Genesis chronology makes Ishmael the only son during a clearly defined period, while it never makes Isaac an only son. The Qur'an's sequence places the sacrifice before Isaac is announced. Thus, when the two accounts are compared carefully, the Qur'anic presentation reads coherently without needing to reinterpret "only son" as "unique covenant son."
The fairest conclusion is therefore modest but meaningful: the chronological argument does not prove the whole of Islam on its own, and it does not erase Genesis 22:2's explicit reference to Isaac. What it does show is that the traditional Muslim identification of Ishmael is not an arbitrary later invention. It is supported by the Qur'an's narrative order and by a serious difficulty within Genesis's own chronology. For a reader assessing the two accounts on internal coherence, that is evidence worth taking seriously.