Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) says: I gave the ritual bath (ghusl) to the Messenger of Allah (peace and blessings be upon him). I looked to see in him (peace and blessings be upon him) what is usually seen in a dead body, but I saw nothing. I found him (peace and blessings be upon him) pure, both living and dead. His (peace and blessings be upon him) burial was entrusted to four men: Sayyiduna Ali (may Allah be pleased with him), Sayyiduna al-Abbas and Sayyiduna al-Fadl (may Allah be pleased with them both), and Salih (may Allah be pleased with him), the freed slave of the Messenger of Allah (peace and blessings be upon him). A niche grave (lahd) was dug for the Messenger of Allah (peace and blessings be upon him), and unbaked bricks were set upright over it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7043