مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1928
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn "Abbas said: The Messenger of Allah (ﷺ) prayed in Madinah, when he was a resident and not travelling, seven [rak"ahs] and eight [rak"ahs].
Musnad Ahmad 1929Sahih because of corroborating evidence, al-Bukhari (1174) a