Ma'dan bin Talhah said: I said to Thawban (may Allah be pleased with him), the freed slave of the Prophet (peace and blessings be upon him): Tell me of a deed by which Allah will benefit me. He remained silent. I said again: Guide me to a deed by which Allah will benefit me. He again remained silent. I said a third time: Tell me of a deed by which Allah will benefit me. Then he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "There is no servant who prostrates once to Allah except that Allah raises him one degree by it and removes one sin from him by it." Ma'dan said: Then I met Abu al-Darda' (may Allah be pleased with him), and he also narrated the same to me. In another narration from al-Awza'i these words are additional: "Make prostrations to Allah binding upon yourself."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4567