Riyad as-Salihin

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "(The performance of) 'Umrah is an expiation for the sins committed between it and the previous 'Umrah; and the reward of Hajj Mabrur (i.e., one accepted) is nothing but Jannah."

[Al-Bukhari and Muslim].