Sunan an Nasai
2781
Sahih+2

It was narrated from Hafsah, the wife of the Prophet, that she said: "O Messenger of Allah, why is it that the people have exited Ihram for Umrah but you have not exited your Ihram for Umrah? He said: "I have matted my hair and garlanded my Hadi, so I will not exit Ihram until I have offered the sacrifice

SahihAbu Ghuddah
SahihAl-Albani