Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 497

Narrated Nafi:

Abdullah bin Umar set out for Umra during the period of afflictions, and he said, "If I should be stopped from visiting the Kaba, I will do what we did when we were with Allah's Apostle." He assumed Ihram for 'Umra in the year of Al-Hudaibiya.