Musnad Ahmad 27:1931

'Abd al-Razzaq narrated to us, I heard 'Ubayd Allah ibn 'Umar and 'Abd al-'Aziz ibn Abi Rawwad narrating from Nafi', who said: Ibn 'Umar went out intending to perform Hajj at the time when al-Hajjaj descended upon Ibn al-Zubayr. It was said to him: "The people will have fighting between them, and we fear that they will block you." He said: "There has certainly been for you in the Messenger of Allah an excellent pattern" [Al-Ahzab: 21]. "Therefore, I will do as the Messenger of Allah (peace and blessings of Allah be upon him) did. I call you to witness that I have made an 'Umrah obligatory." Then he went out until, when he was at Zahral-Bayda', he said: "The matter of Hajj and 'Umrah is but one. I call you to witness that I have made Hajj obligatory along with my 'Umrah." And he offered a sacrificial animal which he had bought at Qudayd. He set off until he arrived at Makkah, and he performed Tawaf around the House and between al-Safa and al-Marwah, and he did not add anything to that. He did not slaughter, he did not shave, he did not trim, and he did not exit from anything he had entered into Ihram for until it was the Day of Sacrifice (Yawm al-Nahr). Then he slaughtered and shaved. Then he considered that he had fulfilled his Tawaf for the Hajj and the 'Umrah by his first Tawaf. Then he said: "This is how the Messenger of Allah (peace and blessings of Allah be upon him) did."