Narrated Abu Huraira: Allah's Apostle said, "(The performance of) 'Umra is an expiation for the sins committed (between it and the previous one). And the reward of Hajj Mabrur (the one accepted by Allah) is nothing except Paradise."
— Sahih Bukhari, Volume 3, Book 27: Minor Pilgrammage (Umra), Hadith #1
Narrated Abu Huraira: Allah's Apostle said, "(The performance of) 'Umra is an expiation for the sins committed (between it and the previous one). And the reward of Hajj Mabrur (the one accepted by Allah) is nothing except Paradise."
This hadith is from the book of Minor Pilgrammage (Umra) in Sahih Bukhari, compiled by Imam al-Bukhari. It is hadith number 1 in book 27 of volume 3.
This hadith is referenced in the following topics: Hajj, Umrah.