According to Islamic Traditions, it was Isma'il (AS), the first son of Ibrahim (AS), who was meant for sacrifice and not Ishaq (Isaac) (AS). The Biblical narratives differ with the Qur’anic version suggesting, instead, that it was Isaac – the second son of Ibrahim (AS), born through Sarah, who was meant for the sacrifice. Genesis (chapter 22) says: "Then God said, "Take your son, your only son, Isaac, whom you love…" The problem with this verse is that Isaac was not Abraham's only son. Before Isaac was born, there was Ishmael. Is it possible some zealous scribe had replaced the word Ishmael with Isaac into the verse?
Since the Qur’anic story about sacrifice did not specifically mention Isma’il (AS) by name, some Jews and Christians have suggested that the lad meant for sacrifice was Isaac. However, if one follows the sequence of verses it becomes clear that Ishaq (AS) was not meant in the Qur’anic story. In regard to the verse, "So We gave him the good news of a forbearing son," Imam Ibn Kathir (R) states in his tafsir (exegesis): "And this son is Isma’il (AS) for he is the first son whose good news was brought to Ibrahim (AS). He is older than Ishaq (AS), according to both Muslims and the Ahl-e-kitab (People of the Book – Jews and Christians). It is even said in their Scripture that Isma’il (AS) was born when Ibrahim was 86 years old and Ishaq (AS) was born when Ibrahim (AS) was 99. Moreover, their scripture states that Allah ordered Ibrahim (AS) to sacrifice his only son and in another version his firstborn. And, at this spot, they inserted falsely the name of Ishaq (AS) against the text of their very Scripture. The reason they inserted Ishaq (AS) is that he is their father whereas Isma’il (AS) is the father of the Arabs. They added Ishaq (AS) out of envy and brushed away ‘only son’ by saying that Isma’il (AS) and his mother had already been to Makkah. This is a fanciful explanation since we never say ‘only son’ except to a person who has no more than one son. Moreover, the firstborn has got a special place [in the heart of his father] that is not given to the following children and the order to sacrifice him is, therefore, a greater test… Moreover, God's Book (the Qur’an) is a witness, and points to the fact that it is Isma’il (AS) because it said that the son who was patient and that he is the sacrificed. Only afterwards, He (Allah) said: ‘And We gave him the good news of Ishaq, a prophet, one of the Righteous’ (37:112) and when the Angels brought the good news of Ishaq to Ibrahim they said: ‘Fear not,’ and they gave him the ‘glad tidings of a son endowed with knowledge.’ And [Allah] the Most High said: ‘We gave her [Sarah] glad tidings of Ishaq, and after him, of Yaqub (Jacob)" (11:71) -- meaning that in the lifetime of Abraham and Sarah, Isaac will beget a child that he will call Yaqub implying that Ishaq will have a progeny. We have already explained why it is not possible that Ishaq be sacrificed while still a child, i.e., because God promised them [Ibrahim and Sarah] that he [Ishaq] will have a progeny. On the other hand, Isma’il was described as forbearing and he fits that description."
As can be seen from above narrative, Imam Ibn Kathir nullifies the Judeo-Christian argument by simply making the point that Ibrahim (AS) was given the good news about the birth of Ishaq (AS) who would go on to father Yaqub (AS). Thus, it was not Ishaq (AS), but Isma’il (AS) who was meant for sacrifice.