Mutarrif narrates: I was sitting with some people from Quraysh when a man came and began to pray. He was performing ruku' and sajdah but was not sitting (for tashahhud). I said: "By Allah! I cannot make out whether this man will finish his prayer after an even number or after an odd number." They said: "Why don't you get up, go to him and tell him so?" Mutarrif says: I got up and said: "O servant of Allah! I cannot tell whether you will finish your prayer after an even number of rak'ahs or after an odd number." He replied: "But Allah Almighty knows. I heard the Prophet (peace and blessings be upon him) say: 'Whoever performs one prostration for Allah Almighty, Allah Almighty records one good deed for him because of it, removes one sin from him because of it, and raises him one degree because of it.'" Mutarrif says: I asked: "Who are you?" He replied: "Abu Dharr." I went back to my companions and said: "May Allah Almighty repay you as bad companions are repaid! You directed me to teach one of the Companions of the Prophet (peace and blessings be upon him)!" In one narration the wording is: I saw him standing for a long time and performing ruku' and sajdah abundantly. I mentioned this to him, and he said: "I have spared no effort in praying well, for I heard the Prophet (peace and blessings be upon him) say: 'Whoever performs one ruku' or one sajdah is raised one degree by it, and one sin is erased from him by it.'"
Ahmad recorded all of these narrations, and al-Bazzar recorded similar narrations through various chains; the narrators of some of them are the narrators of the Sahih.
Al-Tabarani recorded it in al-Mu'jam al-Awsat.