Sahih Muslim 494
Sahih Muslim · Book 4: The Book of Prayers · Moderation In Prostration; Placing The Hands On The Ground, Keeping The Elbows Up, Away From The Sides, And Lifting The Belly Up Off The Thighs When Prostrating
Al-Bira' (b. 'Azib) reported:
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى ، قَالَ أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ إِيَادٍ ، عَنْ إِيَادٍ ، عَنِ الْبَرَاءِ ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا سَجَدْتَ فَضَعْ كَفَّيْكَ وَارْفَعْ مِرْفَقَيْكَ " .
The Messenger of Allah (ﷺ) said. When you prostrate yourself, place the palms of your hands on the ground and raise your elbows.