It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Perform Hajj and Umrah one after the other, for they both wipe away sins just as the furnace removes the impurities of iron."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13594