The Prophet ﷺ said, "This is an Umrah we have benefited from. Whoever does not have a sacrificial animal with him, let him exit the state of ihram completely. Umrah has been incorporated into Hajj until the Day of Resurrection."
حدثنا عثمان بن أبي شيبة أن محمد بن جعفر حدثهم عن شعبة عن الحكم عن مجاهد
عن النبي ﷺ أنه قال هذه عمرة استمتعنا بها فمن لم يكن عنده هدي فليحل الحل كله وقد دخلت العمرة في الحج إلى يوم القيامة
Muslim narrated it in the chapter on Hajj, in the section on the permissibility of Umrah during the months of Hajj, hadith no. 1241, from the hadith of Muhammad bin Jafar, by this route, and Baghawi graded it sahih in Sharh al-Sunnah, hadith no. 1886.