Abdur Rahman bin 'Amr al-Awza'i عبد الرحمن بن عمرو أبو عمرو الأوزاعي · The Book of Salah

It 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.