Musannaf Ibn Abi Shayba 21:729

'Abd al-Rahim ibn Sulayman narrated to us, from Isma'il ibn Abi Khalid, from Jubayr ibn 'Adi, who said: I was informed that 'Ali ibn Abi Talib used to say when the deceased was placed into his grave: "In the name of Allah, and upon the creed of the Messenger of Allah, may Allah bless him and grant him peace, and in confirmation of Your Book and Your Messengers, and in certainty of the resurrection after death. O Allah, make his grave spacious for him, and give him glad tidings of Paradise."