Sahih Muslim — The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship — Hadith No: 6696
Translation
Abu Huraira reported Allah's Apostle (ﷺ) as saying:Anyone amongst the Muslims, three of whose children die, and he resigns himself calmly to the will of God, Fire will not touch him but for the fulfilment of the oath