مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2101
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) kept away from his wives for a month. When twenty nine days had passed, Jibreel came to him and said: Your oath has been fulfilled; the month is over.
Musnad Ahmad 2103Its isnad is saheeh]