Musnad Ahmad 31:231

Sulayman ibn Dawud narrated to us, Imran informed us, from Qatadah, from Abdullah ibn Abi Utbah, from Abu Sa’id al-Khudri, from the Prophet, peace and blessings of Allah be upon him, who said: "This House shall surely be performed Hajj to, and it shall surely be performed Umrah to, after the emergence of Gog and Magog."