Sahih Muslim Book 4, Hadith Number 999.

Chapter : How the limbs should work in prostration and forbiddance to fold clothing and hair and plaiting of hair in the prayer.

Al-Bira’ (b. ‘Azib) reported: The Messenger of Allah (may peace be upon him) said: When you prostrate yourself, place the palms of your hands on the ground and raise your elbows.