The Book of Funerals
21/44. Chapter:
Hastening With The Janazah
Sunan an-Nasai
أَخْبَرَنَا يَحْيَى بْنُ دُرُسْتَ، قَالَ حَدَّثَنَا أَبُو إِسْمَاعِيلَ، عَنْ يَحْيَى، أَنَّ أَبَا سَلَمَةَ، حَدَّثَهُ عَنْ أَبِي سَعِيدٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا مَرَّتْ بِكُمْ جَنَازَةٌ فَقُومُوا فَمَنْ تَبِعَهَا فَلاَ يَقْعُدْ حَتَّى تُوضَعَ " .
It was narrated from Abu Sa'eed that the Messenger of Allah said: "When a funeral passes by you, stand up, and whoever follows it, let him not sit down until it is put down (in the grave)."
Reference : Sunan an-Nasa'i 1914In-book reference : Book 21, Hadith 97English translation : Vol. 3, Book 21, Hadith 1915