(21) The Book of Funerals
كتاب الجنائز
(44) Chapter: Hastening With The Janazah
(44) باب السُّرْعَةِ بِالْجَنَازَةِ ‏
Sunan an-Nasa'i 1910 
It was narrated from Abu Hurairah, who attributed it to the Prophet:
"Hasten with the Janazah, for if it was righteous then your are taking it toward something good, and if it was otherwise, then it is an evil of which you are relieving yourselves."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، يَبْلُغُ بِهِ النَّبِيَّ صلى الله عليه وسلم قَالَ ‏ "‏ أَسْرِعُوا بِالْجَنَازَةِ فَإِنْ تَكُ صَالِحَةً فَخَيْرٌ تُقَدِّمُونَهَا إِلَيْهِ وَإِنْ تَكُ غَيْرَ ذَلِكَ فَشَرٌّ تَضَعُونَهُ عَنْ رِقَابِكُمْ ‏"‏ ‏.‏
Grade :  Sahih (Darussalam)
Reference : Sunan an-Nasa'i 1910
In-book reference : Book 21, Hadith 93
English translation : Vol. 3, Book 21, Hadith 1911