مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2189
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that The Messenger of Allah (ﷺ) delayed 'Isha' one night until the people had fallen asleep then woken up, then had fallen asleep then woken up. Qais said: Then 'Umar bin al-Khattab came and said: The prayer, O Messenger of Allah! So he came out and led them in prayer, and [Qais] did not state that they did wudoo’.
Musnad Ahmad 2195Its isnad is saheeh]