صحيح البخاري
Sahih Bukhari
كتاب الجنائز
The Book of Al-Janaiz (Funerals)
بَابُ مَنْ تَبِعَ جَنَازَةً فَلاَ يَقْعُدُ حَتَّى تُوضَعَ عَنْ مَنَاكِبِ الرِّجَالِ، فَإِنْ قَعَدَ أُمِرَ بِالْقِيَامِ:
(48) Chapter. Whoever accompanies a funeral procession should not sit till the coffin is put down from the shoulders of men, and if someone sits before this, then he is to be ordered to stand up.
2 hadith
Hadith 1309
Narrated Sa`id Al-Maqburi: That his father said, "While we were accompanying a funeral procession, Abu Huraira got hold of the hand of Marwan and they sat down before the coffin was put down. Then Abu Sa`id came and took hold of Marwan's hand and said, "Get up. By Allah, no doubt this (i.e. Abu Huraira) knows that the Prophet forbade us to do that." Abu Huraira said, "He (Abu Sa`id) has spoken the truth."
Hadith 1310
Narrated Abu Sa`id Al-Khudri: The Prophet said, "When you see a funeral procession, you should stand up, and whoever accompanies it should not sit till the coffin is put down."