مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3497
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn ‘Abbas (رضي الله عنه) that The Messenger of Allah (ﷺ) said: "Allah, may He be glorified and exalted, has decreed Hajj for you." al-Aqra` bin Habis said: Is it (every year) for ever, O Messenger of Allah? He said: “No, it is one Hajj. If I said yes, it would become obligatory.”
Musnad Ahmad 3520A saheeh hadeeth; this is a da’eef isnad]