The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 2084
Sha'bi reported that the Messenger of Allah (may peace be upon him) observed prayer over a grave after the dead was buried and he recited four takbirs over him. Shaibani said: I said to Sha'bi: Who narrated it to you? He said: An authentic one, 'Abdullah b. 'Abbas. This is the word of a hasan hadith. In the narration of Ibn Numair (the words are): The Messenger of Allah (may peace be upon him) went to the grave which had been newly prepared and prayed over it, and they also prayed who were behind him and he recited four takbirs. I said to 'Amir: Who narrated it to you? He said: An authentic one who saw him, i e. Ibn 'Abbas.