Hadith 6:404
Waki’ narrated to us, from Sufyan, from Ibn Jurayj, who said: When the Messenger of Allah (peace and blessings of Allah be upon him) was at a funeral, he would be silent for the most part and speak to himself.
حدثنا وكيع عن سفيان عن بن جريج قال كان رسول الله صلى الله عليه وسلم إذا كان في جنازة أكثر السكوت وحدث نفسه