Sayyiduna Uqbah bin Amir (may Allah be pleased with him) narrates: I came with twelve riders until we arrived at (the blessed city of) the Prophet (peace and blessings be upon him). My companions said: Who will look after the camels, so that we can go and benefit from the Prophet (peace and blessings be upon him), and when we come back we will tell him what we heard from the Prophet (peace and blessings be upon him)? I said: I will do it. Then afterwards I thought: In this I will be at a loss, because whatever my companions hear, I will not have heard it from the Prophet (peace and blessings be upon him). One day, when I was present, I heard a man narrating: The Prophet (peace and blessings be upon him) said: "Whoever performs complete ablution and then stands for the prayer becomes, with regard to his sins, as he was on the day his mother gave birth to him."
Imam al-Tabarani recorded this report in al-Mu'jam al-Awsat; the complete report has already passed in the Book of Faith (Kitab al-Iman), and the discussion of it has also passed.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1143