Beautiful Hadith is about Wudu

Amr b Sa'id b al-As RA reported: I was with Uthman, and he called for ablution water and said: I heard Allah's Messenger (peace be upon him) say: When the time for a prescribed prayer comes, if any Muslim performs ablution well and offers his prayer with humility and bowing, it will be an expiation for his past sins, so long as he has not committed a major sin; and this applies for all times. (Muslim - Book 2, Hadith 441)