Musnad Ahmad 3:115

Abu Abd al-Rahman al-Muqri narrated to us, Haywah narrated to us, Abu Aqil informed us that he heard al-Harith, the freed slave of Uthman, say: Uthman sat one day and we sat with him. The mu'adhdhin came to him, so he called for water in a vessel—I think it contained a mudd—and he performed ablution. Then he said: "I saw the Messenger of Allah (peace and blessings of Allah be upon him) perform ablution like this ablution of mine." Then he said: "Whoever performs ablution like this ablution of mine, then stands and performs the Dhuhr prayer, what is between it and the morning prayer is forgiven for him. Then he performs the Asr prayer, what is between it and the Dhuhr prayer is forgiven for him. Then he performs the Maghrib prayer, what is between it and the Asr prayer is forgiven for him. Then he performs the Isha prayer, what is between it and the Maghrib prayer is forgiven for him. Then perhaps he spends his night tossing and turning, then if he gets up and performs ablution and performs the morning prayer, what is between it and the Isha prayer is forgiven for him. And these are the good deeds that remove the evil deeds." They said: "These are the good deeds, but what are the enduring good deeds (al-baqiyat), O Uthman?" He said: "They are: La ilaha illa Allah (There is no god but Allah), Subhan Allah (Glory be to Allah), Al-hamdu lillah (Praise be to Allah), Allahu Akbar (Allah is the Greatest), and La hawla wa la quwwata illa billah (There is no power and no strength except by Allah)."