(1) باب فضله وبيان من فرض عليه
Abu Hurairah (RAA) narrated that the Messenger of Allah said, "The performance of 'Umrah is an expiation for all the sins committed (between this 'Umrah and the previous one), and the reward for Hajj Mabrur (the one accepted by Allah or the one which was performed without doing any wrong) is nothing save Paradise." Agreed upon.
Reference: Bulugh al-Maram 708
In-book reference: Book 6, Hadith 1
English translation: Book 6, Hadith 728