Musnad Ahmad 658:157

Yazid narrated to us, he said: Zakariya informed us, from Abu Ishaq, from Al-Bara’ ibn ‘Azib, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) performed ‘Umrah before he performed Hajj, and he performed ‘Umrah before he performed Hajj, and he performed ‘Umrah before he performed Hajj." ‘Aishah said: "He certainly knew that he performed four ‘Umrahs, along with the ‘Umrah that he performed with his Hajj."