Sunan an-Nasa'i 452
سنن النسائي#452SahihIt was narrated from Anas bin Malik that the prayers were enjoined in Makkah, and that two angels came to the Messenger of Allah (ﷺ) and took him to Zamzam, where they split open his stomach and took out his innards in a basin of gold, and washed them with Zamzam water, then they filled his heart with wisdom and knowledge
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 5:5