Nafi reported,

Ubaydullah bin Abdullah and Salim bin Abdullah reported that they both spoke to Abdullah bin Umar, saying to him, "It would be better if you stayed home this year, for we fear you may not be able to reach the House."He replied, "We set out with the Prophet ﷺ, and the disbelievers of Quraysh blocked our way to the House. So the Prophet ﷺ sacrificed his offerings, and his companions shaved or shortened their hair."Then he said, "I call you to witness that I have made umrah obligatory upon myself. If I am given clear access to the House, I will perform tawaf. But if I am prevented from reaching the House, I will do as the Messenger of Allah ﷺ did."He travelled on for a while, then said, "I see that the two are one and the same. I call you to witness that I have made hajj obligatory upon myself along with my umrah."He then performed a single tawaf and a single saee, and with that he completed both rites together.

عن نافع

أن عبيد الله بن عبد الله، وسالم بن عبد الله أخبراه أنهما كلما عبد الله بن عمر وقال له: لو أقمت العام، فإني أخاف أن لا تصل إلى البيت قال: خرجنا مع النبي ﷺ فحال كفار قريش دون البيت، فنحر النبي ﷺ هداياه، وحلق وقصر أصحابه. وقال: أشهدكم أني أوجبت عمرة، فإن خلي بيني وبين البيت طفت، وإن حيل بيني وبين البيت صنعت كما صنع رسول الله ﷺ، فسار ساعة، ثم قال: ما أرى شأنهما إلا واحدا، أشهدكم أني قد أوجبت حجة مع عمرتي، فطاف طوافا واحدا، وسعيا واحدا حتى حل منهما جميعا.