Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever loses two or three children who had not reached puberty, and bears it patiently, counting it as a means of reward, they will be a screen for him against Hell."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7137