مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2508
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: “Seek it in the last ten nights of Ramadan, the twenty ninth or the twenty seventh or the twenty fifth.”
Musnad Ahmad 2520Its isnad is saheeh, al-Bukhari (2021)]