Sayyiduna Abu Musa al-Ash'ari (may Allah be pleased with him) narrates: The Messenger of Allah (peace and blessings be upon him) sent me to the land of my people. When the time of Hajj came, he (peace and blessings be upon him) performed Hajj and so did I. When I arrived, he (peace and blessings be upon him) was at a place called "al-Abtah". He (peace and blessings be upon him) asked: "How did you say the talbiyah?" I said: Like this: 'Labbayka bi-hajjin ka-hajji Rasulillah (peace and blessings be upon him)' (Here I am, for a Hajj like the Hajj of the Messenger of Allah (peace and blessings be upon him)). He (peace and blessings be upon him) said: "You did well." Then he asked me: "Have you brought a sacrificial animal with you?" I said: No. So he (peace and blessings be upon him) said: "Then go and perform tawaf of the House of Allah and the sa'i between Safa and Marwah, and then leave the state of ihram." He says: So I went and did just as I had been commanded. Then I went to a woman of my people; she washed my head with lote-tree leaves and combed it. Then I put on ihram for Hajj on the Day of Tarwiyah. So during the lifetime of the Messenger of Allah (peace and blessings be upon him), in the time of Sayyiduna Abu Bakr (may Allah be pleased with him) and in the early part of the caliphate of Sayyiduna Umar (may Allah be pleased with him), I kept giving people the same fatwa that the Messenger of Allah (peace and blessings be upon him) had given me. While I was giving people this very fatwa near the Black Stone or the Station of Ibrahim, a man suddenly came and said to me quietly: Do not be hasty with your fatwa; the Commander of the Believers has made some change (that is, in the rites of Hajj). So I announced: O people! Whomever we have given a fatwa about anything should wait patiently; the Commander of the Believers is coming, so follow him. When Sayyiduna Umar (may Allah be pleased with him) arrived, I went to him and asked: Have you introduced something new in the rites? He said: Yes! We take the Sunnah of our Prophet (peace and blessings be upon him): he (peace and blessings be upon him) did not leave ihram before offering the sacrifice; and if we take the Qur'an, it tells us to "complete the Hajj and Umrah for Allah" [Surah al-Baqarah: 196].
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8871