مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2617
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
Qatadah said: I heard Moosa bin Salamah say: l asked Ibn ‘Abbas (رضي الله عنه): I am in Makkah; how should I pray? He said: Two rak'ahs, the Sunnah of Abul-Qasim (ﷺ).
Musnad Ahmad 2632Its isnad is saheeh, Muslim (688)]