It is narrated from Muhammad bin Ka'b al-Qurazi (may Allah have mercy on him) that he said: "The one of his two sons whom Allah Almighty commanded Ibrahim (peace be upon him) to slaughter was Isma'il (peace be upon him), and we find this in the Book of Allah, in the account of Ibrahim (peace be upon him) and the command given to him to slaughter his son, that it was Isma'il (peace be upon him). The proof of this is that when Allah Almighty completed the account of the one of Ibrahim's two sons who was to be slaughtered, He said: 'And We gave him glad tidings of Ishaq, a Prophet from among the righteous' [Surah al-Saffat: 112] . Then in another place He says: 'So We gave her glad tidings of Ishaq, and after Ishaq, of Ya'qub' [Surah Hud: 71] , that is, glad tidings of a son and then of a grandson. So Allah Almighty could not command the slaughter of Ishaq when He had a promise concerning him which He had made to him (that Ya'qub would be born from him). So the one whom he was commanded to slaughter could be none other than Isma'il."