Sahih Muslim 1230a

Yahya ibn Yahya said: I read to Malik, from Nafi, that Abdullah ibn Umar (may Allah be pleased with them) set out to perform Umra during the time of civil strife. He said: If I am prevented from reaching the House, we will do as we did with the Messenger of Allah. He set out and entered ihram for Umra. When he reached al-Bayda, he turned to his companions and said: The two rites have one ruling. I call you to witness that I have made Hajj obligatory upon myself along with Umra. He continued until he came to the House and circumambulated it seven times, and walked between al-Safa and al-Marwa seven times, adding nothing to that. He considered it sufficient for himself and offered a sacrifice.