Tafsir of As-Saffat 37:101

Thus, by saying 'forbearing' in: فَبَشَّرْ‌نَاهُ بِغُلَامٍ حَلِيمٍ (So, We gave him the good news of a forbearing boy- 101), it was indicated that this newborn would demonstrate such patience, control and forbearance in his life as would be exemplary in the world. The birth of this son had a background of its own. When Sayyidah Sarah (رض) realized that she is not being blessed with children, she took herself to be barren. On the other hand, the Pharaoh had given his daughter named Hajirah (رض) as gift to Sayyidah Sarah (رض) ، so that she could help her in household chores. Sayyidah Sarah (رض) passed on this very Hajirah as gift to Sayyidna Ibrahim (علیہ السلام) who married her. Then the son mentioned here was born to this Hajirah (رض) and he was named Ismail (علیہ السلام) .