From Sahih Bukhari (Hadith 101):
Narrated Abu Sa`id Al-Khudri:Some women requested the Prophet (ﷺ) to fix a day for them as the men were taking all his time. On that he promised them one day for religious lessons and commandments. Once during such a lesson the Prophet said, "A woman whose three children die will be shielded by them from the Hell fire." On that a woman asked, "If only two die?" He replied, "Even two (will shield her from the Hell-fire)
Reference: Bukhari 101