Sahih al-Bukhari 1381
صحيح البخاري#1381SahihNarrated Anas bin Malik:Allah's Messenger (ﷺ) said, "Any Muslim whose three children died before the age of puberty will be granted Paradise by Allah because of His mercy to them
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 23:133