مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2129
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Umar and Ibn 'Abbas that They testified that the Messenger of Allah (ﷺ) said, when he was on the minbar: “People should stop neglecting Jumu’ah or Allah will put a seal on their hearts and they will be recorded as being among the negligent.”
Musnad Ahmad 2132A saheeh hadeeth]