Humran, the freed slave of 'Uthman reported:

I brought for Uthman b. 'Affan the ablution water. He performed ablution and then said: Verily the people narrate from the Messenger of Allah (ﷺ) a hadith. I do not know what these are. but (I know this fact) that I saw the Messenger of Allah (ﷺ) perform ablution like this ablution of mine and then he said: He who performed ablution like this, all his previous sins would be expiated and his prayer and going towards the mosque would have an extra reward. In the tradition narrated by Ibn 'Abda (the words are):" I came to Uthman and he performed ablution."

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَأَحْمَدُ بْنُ عَبْدَةَ الضَّبِّيُّ، قَالاَ حَدَّثَنَا عَبْدُ الْعَزِيزِ، - وَهُوَ الدَّرَاوَرْدِيُّ - عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ حُمْرَانَ، مَوْلَى عُثْمَانَ قَالَ أَتَيْتُ عُثْمَانَ بْنَ عَفَّانَ بِوَضُوءٍ فَتَوَضَّأَ ثُمَّ قَالَ إِنَّ نَاسًا يَتَحَدَّثُونَ عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَحَادِيثَ لاَ أَدْرِي مَا هِيَ إِلاَّ أَنِّي رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم تَوَضَّأَ مِثْلَ وُضُوئِي هَذَا ثُمَّ قَالَ ‏

‏ مَنْ تَوَضَّأَ هَكَذَا غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ وَكَانَتْ صَلاَتُهُ وَمَشْيُهُ إِلَى الْمَسْجِدِ نَافِلَةً ‏

‏ ‏.‏ وَفِي رِوَايَةِ ابْنِ عَبْدَةَ أَتَيْتُ عُثْمَانَ فَتَوَضَّأَ ‏.‏