مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3471
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Moosa bin Salamah said: I asked Ibn ‘Abbas (رضي الله عنه) about praying in al-Batha', if I missed the prayer in congregation. He said: (Pray) two rak'ahs; that is the Sunnah of Abul-Qasim (ﷺ).
Musnad Ahmad 3494Saheeh, Muslim (688)]