Sunan An-Nasa'i

It was narrated from Yazid bin Thabit that:they went out with the Messenger of Allah one day and he saw a new grave. He said: ""What is this?"" They said: ""This is so-and-so, the freed slave woman of Banu so-and-so"" - whom Messenger of Allah knew - ""She died at midday and we did not like to wake you up when you were fasting and taking a nap."" The Messenger of Allah stood (for prayer) and the people formed rows behind him. He said four Takbirs over her then he said: ""If anyone among you dies while I am still among you, inform me, for my prayer for his is a mercy