Amr bin Maymun said: I heard Sayyiduna Uthman (may Allah be pleased with him), and he seldom narrated hadith from the Messenger of Allah (peace and blessings be upon him), say: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever performs ablution as he has been commanded and prays as he has been commanded comes out of his sins as on the day his mother gave birth to him."
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 148