Umayr bin Sa'id said: I offered the funeral prayer over Ibn al-Mukaffaf behind Sayyiduna Ali bin Abi Talib (may Allah be pleased with him), and he said four takbirs. Then he came to his grave and said: 'Allahumma abduka wa waladu abdika nazala bika wa anta khayru manzulin bihi, Allahumma wassi' lahu mudkhalahu waghfir lahu dhanbahu, fa inna la na'lamu bihi illa khayran wa anta a'lamu bihi' (O Allah, this is Your servant and the son of Your servant; he has come to You as a guest, and You are the best of hosts. O Allah, make his grave spacious for him and forgive him his sins; we know nothing of him but good, and You know him better.)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6950