(4) The Book of Prayers
كتاب الصلاة
(45) Chapter: 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
(45) باب الاِعْتِدَالِ فِي السُّجُودِ وَوَضْعِ الْكَفَّيْنِ عَلَى الأَرْضِ وَرَفْعِ الْمِرْفَقَيْنِ عَنِ الْجَنْبَيْنِ وَرَفْعِ الْبَطْنِ عَنِ الْفَخِذَيْنِ فِي السُّجُودِ
Sahih Muslim 494 

Al-Bira' (b. 'Azib) reported:

The Messenger of Allah (ﷺ) said. When you prostrate yourself, place the palms of your hands on the ground and raise your elbows.
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 ‏"‏ ‏.‏
Reference : Sahih Muslim 494
In-book reference : Book 4, Hadith 266
USC-MSA web (English) reference : Book 4, Hadith 999
  (deprecated numbering scheme)