Language:
كتاب الجنائز
23  
Funerals (Al-Janaa'iz)
(47)
Chapter: when should one sit after standing for the funeral procession?
(47)
باب مَتَى يَقْعُدُ إِذَا قَامَ لِلْجَنَازَةِ
Sahih al-Bukhari 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."

حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، عَنْ سَعِيدٍ الْمَقْبُرِيِّ، عَنْ أَبِيهِ، قَالَ كُنَّا فِي جَنَازَةٍ فَأَخَذَ أَبُو هُرَيْرَةَ ـ رضى الله عنه ـ بِيَدِ مَرْوَانَ فَجَلَسَا قَبْلَ أَنْ تُوضَعَ، فَجَاءَ أَبُو سَعِيدٍ ـ رضى الله عنه ـ فَأَخَذَ بِيَدِ مَرْوَانَ فَقَالَ قُمْ فَوَاللَّهِ لَقَدْ عَلِمَ هَذَا أَنَّ النَّبِيَّ صلى الله عليه وسلم نَهَانَا عَنْ ذَلِكَ‏.‏ فَقَالَ أَبُو هُرَيْرَةَ صَدَقَ‏.‏
Reference : Sahih al-Bukhari 1309
In-book reference : Book 23, Hadith 67
USC-MSA web (English) reference : Vol. 2, Book 23, Hadith 396
  (deprecated numbering scheme)