And We gave him the glad tidings of Ishaq -- a Prophet from the righteous,
and,
فَبَشَّرْنَـهَا بِإِسْحَـقَ وَمِن وَرَاءِ إِسْحَـقَ يَعْقُوبَ
So, We gave her glad tidings of Ishaq and after Ishaq, of Ya`qub. (11;71)
He mentions the son and the son of the son, but He would not have commanded him to sacrifice Ishaq when He had promised that this son would in turn have a son. The one whom He commanded him to sacrifice can only have been Ismail."
Ibn Ishaq said, "I heard him say that often."
Ibn Ishaq reported from Buraydah bin Sufyan bin Farwah Al-Aslami that Muhammad bin Ka`b Al-Qurazi told them that he mentioned that to Umar bin `Abd Al-`Aziz, may Allah be pleased with him, when he was Khalifah, while he was with him in Syria. Umar said to him,
"This is something about which I have never given any thought, but I see that it is as you say."
Then he sent for a man who was with him in Syria, a Jew who had become a Muslim and was committed to Islam, and he thought that he had been one of their scholars. Umar bin Abd Al-Aziz, may Allah be pleased with him, asked him about that.
Muhammad bin Ka`b said, "I was with Umar bin Abd Al-`Aziz.
Umar said to him, `Which of the two sons of Ibrahim was he commanded to sacrifice?'
He said, `Ismail. By Allah, O Commander of the faithful, the Jews know this, but they were jealous of you Arabs because it was your father about whom Allah issued this command and the virtue that Allah mentioned was because of his patience in obeying the command. So they denied that and claimed that it was Ishaq, because he is their father."'
Abdullah bin Al-Imam Ahmad bin Hanbal, may Allah have mercy on him, said,
"I asked my father about which son was to be sacrificed -- was it Ismail or Ishaq?"
He said, "Ismail."
This was mentioned in Kitab Az-Zuhd.
Ibn Abi Hatim said,
"I heard my father say, `The correct view is that the one who was to be sacrificed was Ismail, peace be upon him."'
He said,
"And it was narrated that Ali, Ibn Umar, Abu Hurayrah, Abu At-Tufayl, Sa`id bin Al-Musayyib, Sa`id bin Jubayr, Al-Hasan, Mujahid, Ash-Sha`bi, Muhammad bin Ka`b Al-Qurazi, Abu Ja`far Muhammad bin Ali and Abu Salih, may Allah be pleased with them all, said that the one who was to be sacrificed was Ismail."
Al-Baghawi said in his Tafsir,
"This was the view of `Abdullah bin Umar, Sa`id bin Al-Musayyib, As-Suddi, Al-Hasan Al-Basri, Mujahid, Ar-Rabi` bin Anas, Muhammad bin Ka`b Al-Qurazi and Al-Kalbi."
This was also reported from Ibn Abbas and from Abu `Amr bin Al-`Ala'.
وَبَشَّرْنَاهُ بِإِسْحَقَ نَبِيًّا مِّنَ الصَّالِحِينَ
And We gave him the glad tidings of Ishaq -- a Prophet from the righteous.
having given the glad tidings of the one who was to be sacrificed, who was Ismail, Allah immediately follows that with mention of the glad tidings of his brother Ishaq. This is also mentioned in Surah Hud (11;71) and in Surah Al-Hijr (15;53-55)
نَبِيًّا
(a Prophet),
means, from him there will come a righteous Prophet.
وَبَارَكْنَا عَلَيْهِ وَعَلَى إِسْحَقَ وَمِن ذُرِّيَّتِهِمَا مُحْسِنٌ وَظَالِمٌ لِّنَفْسِهِ مُبِينٌ