It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "An Umrah is an expiation for the sins between it and the next Umrah, and the accepted Hajj (Hajj mabrur) has no reward except Paradise."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8724