مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2113
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that the Prophet (ﷺ) said: "This is an "Umrah which we have joined to Hajj. Whoever does not have a sacrificial animal with him, let him exit ihram completely, for 'Umrah has been incorporated into Hajj until the Day of Resurrection.”
Musnad Ahmad 2115Its isnad is saheeh, Muslim (1241)]