Sayyiduna Uthman Ghani (may Allah be pleased with him) narrates: I saw the Prophet (peace and blessings be upon him) perform ablution, and he performed it well. Then he said: "Whoever performs ablution like this ablution of mine, then comes to the mosque and prays two rak'ahs in it, his past sins are forgiven." (Allamah al-Haythami says:) I say: This narration is in the Sahih, except that it does not contain the words: "then he comes to the mosque and prays two rak'ahs in it."
Bazzar recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2068