Further scrutiny requires that we quote the full passage in surah 37:
99. He said: "I will go to my Lord! He will surely guide me!
100. "O my Lord! Grant me a righteous (son)!"
101. So We gave him the good news of a forbearing son.
102. Then, when (the son) reached (the age of) (serious) work with him, he said: "O my son! I have seen in a vision that I offer thee in sacrifice: now see what is thy view!" (The son) said: "O my father! Do as thou art commanded: thou will find me, if Allah so wills, one of the steadfast!"
103. So when they had both submitted (to Allah), and he had laid him prostrate on his forehead (for sacrifice),
104. We called out to him "O Abraham! ...
105. "Thou hast already fulfilled the vision!" - thus indeed do We reward those who do right.
106. For this was a clear trial-
107. And We ransomed him with a momentous sacrifice:
108. And We left for him among generations (to come) in later times:
109. "Peace and salutation to Abraham!"
110. Thus indeed do We reward those who do right.
111. For he was one of Our believing Servants.
112. And We gave him the good news of Isaac - a prophet,- one of the Righteous.
113. We blessed him and Isaac: but of their progeny are (some) that do right, and (some) that obviously do wrong, to themselves.
It is very obvious that, in this passage, there are two distinct good news, the first one about a forbearing son (the one to be sacrificed) and the second one about Isaac(P). Thus, the sacrificed cannot be Isaac(P) at least not according to the Qur'ân. But, once again, the opponent avoided (willingly?) to quote the full passage and this is frequently their way of doing things. Moreover, those who support that the two news are actually the same show their incompetence with the Qur'ânic style. Such a repetition cannot be imagined nor accepted by anyone who studied the Qur'ân, God's Final Book.
The Opinion Of Ibn Kathîr[1]
The above scan is the exegesis of verse 37:101 "So We gave him the good news of a forbearing son". Here is the translation of the above passage:
"So We gave him the good news of a forbearing son."
And this son is Ishmael(P) for he is the first son whose good news was brought to Abraham(P). He is older than Isaac according to Muslims and ahl al-kitâb (i.e., the People of the Book) too. It is even said in their Scripture that Ishmael(P) was born when Abraham(P) was 86 years old and Isaac(P) was born when Abraham(P) was 99. In their Scripture as well, God is said to have ordered Abraham(P) to sacrifice his only son and in another version his firstborn. And, at this spot, they inserted falsely the name of Isaac(P) against the text of their very Scripture. The reason they inserted Isaac(P) is that he is their father whereas Ishmael(P) is the father of the Arabs. They added Isaac(P) out of envy and brushed away "only son" by saying that Ishmael(P) and his mother had already been to Makkah. This is a mere [farfetched] explanation since we never say "only son" except to a person who hasn't got but 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. Some knowledgeable people were inclined to say that the sacrificed was Isaac(P). This was reported from some people of the salaf (i.e. people of the previous generations) and it was even reported from some Companions(R) but [this opinion] does not have any bearings from the Book [i.e., the Qur'ân] nor from the Sunnah. I think such opinion was received from the Rabbis of ahl al-Kitâb as is without evidence. Moreover, God's Book is a witness and points to the fact that it is Ishmael(P) because the glad tiding said that the son was patient and that he is the sacrificed. Only afterwards, He said: "And We gave him the good news of Isaac - a prophet,- one of the Righteous." and when the Angels brought the good news of Isaac(P) to Abraham(P) they said: " "Fear not," and they gave him glad tidings of a son endowed with knowledge." And the Most High said: " We gave her [Sarah] glad tidings of Isaac, and after him, of Jacob." [11:71] meaning that in the lifetime of Abraham(P) and Sarah(P), Isaac(P) will beget a child that he will call Jacob(P) implying that Isaac(P) will have a progeny. We have already explained why it is not possible that Isaac(P) be sacrificed while still a child i.e., because God promised them [Abraham and Sarah] that he will have a progeny. On the other hand, Ishmael(P) was described as forbearing and he fits that description.
[Note that many commentators including Ibn Kathîr believe that "forbearing" does not fit a child, it can at least describe teenagers for they are old enough to be described as such.]
In a nutshell, the great Qur'ânic commentator Ibn Kathîr adds to our first three arguments two new ones: according to the Bible, the sacrificed is said to be Abraham's(P) only son (or his firstborn in some versions), which cannot fit Isaac(P); according to the Qur'ân, the good news of Isaac(P) said that he would have a progeny and consequently God cannot order Abraham(P) to sacrifice Isaac(P) before the promise is fulfilled. Again, according to the Qur'ân, the sacrificed cannot be Isaac.
The Opinion of cUlûm al-Hadîth
As a matter of fact, there was a debate between Muslim scholars whether the sacrificed was Isaac(P) or Ishmael(P). But the critical study of the reports allows us to drive safe conclusions. Here is the opinion of a scholar of the Science of Hadîth:
The truth is that the reports stating that the Sacrificed is Isaac are part of the Isrâ'îliyyât due to the People of the Book, it was transmitted by those who converted among them like Kacb al-Ahbâr and it was conveyed [from the converts] by some Companions and Followers [tâbicûn] as sign of trust. Later, the scholars who came after them were fooled by such reports and supported that the Sacrificed was Isaac(P). Every book of exegesis [tafsîr] or biography or even history would mention the argument that took place among the salaf. However, some [of those books] would follow the argument by outlining the truth and others wouldn't add any commentary either by conviction or surrender [to these reports].[2]
And further:
The truth is that the Sacrificed is Ishmael(P). This is supported by the Qur'ânic verses and reports from the Companions and Followers and reports rated Marfuc by approval of the Prophet [i.e., when something is said in the presence of the Prophet(P) and he does not oppose it then we consider that it is correct but it does not amount to Sahîh which is, by the way, what the Prophet(P) himself said.].
No wonder that many Companions and Followers and the later scholars of [Qur'ân] and hadîth among which we enumerate great Companions and poles of knowledge like: cAlî, Ibn cUmar, Abû Hurayrah, Abû Tufayl, Sacîd Ibn Jubayr, Mujâhid, al-Sha'by, Al-Hasan al-Basri, Muhammad Ibn Kacb al-Qardhy, Sacîd Ibn al-Musayyab, Abû Jacfar Muhammad al-Bâqir, Abû Sâlih, al-Rabî' Ibn Anas, Abû cAmr Ibn al-cAlâ' and Ahmad Ibn Hanbal and others and it is one version and the strongest from the reports of Ibn cAbbâs.
In Zâd al-Ma'âd by Ibn al-Qayyim: It is the correct opinion according to the knowledgeable among the Companions and Followers and later generations. This opinions was famous among the Arabs before the advent of Islam and it was transmitted from generation to generation in tawâtur and it was also mentioned in the poetry of Umayyah Ibn Abî al-Salt.[3]