Sayyidah Hafsah (may Allah be pleased with her) said: The Messenger of Allah (peace and blessings be upon him) ordered us to come out of ihram on the occasion of the Farewell Hajj, so I said to him: What prevents you (peace and blessings be upon him) from coming out of ihram? He (peace and blessings be upon him) said: "I have matted my hair and garlanded my sacrificial animal, and I cannot come out of ihram until I have sacrificed my animal."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8846