Sunan Abi Dawud — The Rites of Hajj (Kitab Al-Manasik Wa'l-Hajj) — Hadith No: 1806
Translation
Hafsah, wife of the Prophet (ﷺ) said Apostle of Allaah(ﷺ), how is it that the people have put off their ihram and you did not put off your ihram after your ‘Umrah. He said I have matted my hair and garlanded my sacrificial animal, so I shall not put off my ihram till I sacrifice my sacrificial animals