Hafsah, the wife of the Prophet ﷺ, asked, "Messenger of Allah, why have the people exited their state of ihram while you have not done so after your umrah?"He replied, "I have matted my hair and garlanded my sacrificial animal, so I will not exit ihram until I have slaughtered it."
أن حفصة زوج النبي ﷺ قالت: يا رسول الله، ما شأن الناس حلوا ولم تحلل أنت من عمرتك؟ قال: إني لبدت رأسي وقلدت هديي، فلا أحل حتى أنحر.
Malik narrated it in Hajj (180) from Nafi, from Abdullah bin Umar, and mentioned it. Bukhari narrated it in Hajj (1566) and Muslim in Hajj (1229), both through the route of Malik, with the same wording.