(6) باب فَضْلِ مَنْ مَاتَ لَهُ وَلَدٌ فَاحْتَسَبَ
Narrated Abu Sa`id:
The women requested the Prophet, "Please fix a day for us." So the Prophet (ﷺ) preached to them and said, "A woman whose three children died would be screened from the Hell Fire by them," Hearing that, a woman asked, "If two died?" The Prophet (ﷺ) replied, "Even two (would screen her from the (Hell) Fire. " And Abu Huraira added, "Those children should be below the age of puberty. "
Reference: Sahih al-Bukhari 1249, 1250
In-book reference: Book 23, Hadith 13
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 23, Hadith 341