It was narrated from Yazid bin Thabit that they went out with the Messenger of Allah صلی اللہ علیہ وآلہ وسلم 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 صلی اللہ علیہ وآلہ وسلم 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 صلی اللہ علیہ وآلہ وسلم 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 him is a mercy.” (Sahih)