The Description Of The Prayer, With What It Begins And Ends. The Description Of Bowing And Moderation Therein, And Of Prostration And Moderation Therein. Tashah-hud After Each Two Rak'ah Of Four Rak'ah Prayers. Description Ol Sitting Between The Two Prostrations, And In The First Tashah-hud Sahih Muslim 496
Translation
Maimuna reported
When the Messenger of Allah (ﷺ) prostrated himself, if a lamb wanted to pass between his arms, it could pass.