The Messenger of Allah ﷺ said, "Any two Muslim parents who lose three of their children before they reach the age of accountability will have them as a strong fortress shielding them from the Fire."Abu Dharr said, "Messenger of Allah, I have lost two."He replied, "And two as well."Then Ubayy, Abu al-Mundhir, the master of the reciters, said, "Messenger of Allah, I have lost one."The Messenger of Allah ﷺ said, "And even one, provided that this is borne with patience at the first shock of grief."
حدثنا يزيد يعني ابن هارون أخبرنا العوام حدثني أبو محمد مولى عمر بن الخطاب عن أبي عبيدة
قال رسول الله ﷺ أيما مسلمين مضى لهما ثلاثة من أولادهما لم يبلغوا حنثا كانوا لهما حصنا حصينا من النار قال فقال أبو ذر مضى لي اثنان يا رسول الله قال واثنان قال فقال أبي أبو المنذر سيد القراء مضى لي واحد يا رسول الله فقال رسول الله ﷺ وواحد وذلك في الصدمة الأولى
Its isnad is daif due to a break in the chain, and it is a repetition of 4079, and the discussion on it was already given in detail at 3554.