Sahih Bukhari Volume 3, Book 30, Hadith 1935

حَدَّثَنَا عَبْدَانُ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، قَالَ حَدَّثَنِي الزُّهْرِيُّ، عَنْ عَطَاءِ بْنِ يَزِيدَ، عَنْ حُمْرَانَ، رَأَيْتُ عُثْمَانَ ـ رضى الله عنه ـ تَوَضَّأَ، فَأَفْرَغَ عَلَى يَدَيْهِ ثَلاَثًا، ثُمَّ تَمَضْمَضَ وَاسْتَنْثَرَ، ثُمَّ غَسَلَ وَجْهَهُ ثَلاَثًا، ثُمَّ غَسَلَ يَدَهُ الْيُمْنَى إِلَى الْمَرْفِقِ ثَلاَثًا، ثُمَّ غَسَلَ يَدَهُ الْيُسْرَى إِلَى الْمَرْفِقِ ثَلاَثًا، ثُمَّ مَسَحَ بِرَأْسِهِ، ثُمَّ غَسَلَ رِجْلَهُ الْيُمْنَى ثَلاَثًا، ثُمَّ الْيُسْرَى ثَلاَثًا، ثُمَّ قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم تَوَضَّأَ نَحْوَ وُضُوئِي هَذَا، ثُمَّ قَالَ ‏"‏ مَنْ تَوَضَّأَ وُضُوئِي هَذَا، ثُمَّ يُصَلِّي رَكْعَتَيْنِ، لاَ يُحَدِّثُ نَفْسَهُ فِيهِمَا بِشَىْءٍ، إِلاَّ غُفِرَ لَهُ مَا تَقَدَّمَ مِنْ ذَنْبِهِ ‏"‏‏

Narrated By Humran : I saw 'Uthman performing ablution; he washed his hands thrice, rinsed his mouth and then washed his nose, by putting water in it and then blowing it out, and washed his face thrice, and then washed his right forearm up to the elbow thrice, and then the left-forearm up to the elbow thrice, then smeared his head with water, washed his right foot thrice, and then his left foot thrice and said, "I saw Allah's Apostle performing ablution similar to my present ablution, and then he said, 'Whoever performs ablution like my present ablution and then offers two Rakat in which he does not think of worldly things, all his previous sins will be forgiven."