Humran reported,

I brought Uthman bin Affan water for ablution, and he performed the ablution. Then he said, "People are narrating reports from the Messenger of Allah ﷺ that I do not recognize. All I know is that I saw the Messenger of Allah ﷺ perform ablution just as I have performed mine now, and then he said, 'Whoever performs ablution in this manner, his previous sins will be forgiven, and his prayer and his walk to the mosque will count as voluntary reward.'"

Azami 1553

Sahih

عن حمران مولى عثمان قال

أتيت عثمان بن عفان بوضوء، فتوضأ ثم قال: إن ناسا يتحدثون عن رسول الله ﷺ أحاديث لا أدري ما هي؟ إلا أني رأيت رسول الله ﷺ توضأ مثل وضوئي هذا، ثم قال: من توضأ هكذا غفر له ما تقدم من ذنبه، وكانت صلاته ومشيه إلى المسجد نافلة.

الأعظمي 1553صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Wudu
Section
Reward of purification
Numbering
Jami al-Kamil 1553 (2nd edition)
Azami 1553