The Book of The At-Tatbiq (Clasping One's Hands Together)
12/38. Chapter:
The first part of the body that should reach the ground when a person prostrates
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نَافِعٍ، عَنْ مُحَمَّدِ بْنِ عَبْدِ اللَّهِ بْنِ حَسَنٍ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " يَعْمِدُ أَحَدُكُمْ فِي صَلاَتِهِ فَيَبْرُكَ كَمَا يَبْرُكُ الْجَمَلُ " .
It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) said: 'Is there any one of you who kneel as a camel kneels when praying?'"
Reference : Sunan an-Nasa'i 1090In-book reference : Book 12, Hadith 62English translation : Vol. 2, Book 12, Hadith 1091