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
Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "There is no Muslim who performs ablution and does it well, then comes to the mosque and prays two rak'ahs in it, then seeks forgiveness from Allah Almighty, except that Allah Almighty forgives him." I say: Abu Dawud and others recorded this narration in abridged form, leaving out the coming to the mosque and praying in it.
Bazzar recorded it; its chain contains Abdullah bin Sa'id al-Maqburi, who is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2069