The Messenger of Allah ﷺ said, "Whoever has three children pass away before reaching puberty, they will be a strong fortress for him against the Fire."Abu Dharr asked, "What if I have lost two?"He replied, "And two as well."Then Ubayy bin Kaab, the master of the reciters, asked, "What if I have lost only one?"He replied, "And one as well, but that is only if one bears it with patience at the first shock of grief."
حدثنا نصر بن علي الجهضمي حدثنا إسحق بن يوسف حدثنا العوام بن حوشب عن أبي محمد مولى عمر بن الخطاب عن أبي عبيدة بن عبد الله بن مسعود
قال رسول الله ﷺ من قدم ثلاثة لم يبلغوا الحلم كانوا له حصنا حصينا من النار قال أبو ذر قدمت اثنين قال واثنين فقال أبي بن كعب سيد القراء قدمت واحدا قال وواحدا ولكن إنما ذاك عند الصدمة الأولى
[Its isnad is daif] Ibn Majah reported it in the Book of Funerals, Chapter on What Has Been Related Concerning the Reward of One Who Is Afflicted by the Loss of His Child, hadith no. 1606, from Nasr bin Ali with the same chain. Abu Muhammad is majhul (Taqrib), and the chain is disconnected.