Isa bin Yonus bin Abi Ishaq عيسى بن يونس بن أبي إسحاق · The Book on Jana''iz (Funerals)

The Messenger of Allah said: "No one dies and they stand over him crying and saying: 'O what a great man he was! O how respectful he was!' except that two angels are appointed for him to poke him (saying): 'Is that you?'"

"The Messenger of Allah would walk in front of the funeral, as did Abu Bakr, Umar and Uthman."

"The Messenger of Allah passed by the graves of Al-Madinah, so he turned his face towards them and said: (As-Salamu alaikum ya ahlul-qubur! Yaghfirul-lahu lana wa lakun, antum salafuna wa nahnu bil-athar.) 'Peace be upon you O inhabitants of the grave! May Allah forgive us and you; you are our predecessors and we are to follow you.'"