Musnad Ahmed: Hadith 3443

Which do you prefer for me, to pray 'Isha' as an imam (leading the prayer) or to delay it and pray alone? He said: I heard Ibn ‘Abbas (رضي الله عنه) say: The Messenger of Allah (ﷺ) delayed ‘Isha' one night until the people had fallen asleep and woken up, and fallen asleep then woken up (again). Then 'Umar bin al-Khattab (رضي الله عنه) stood up and said: The prayer. ‘Ata’ said: Ibn ‘Abbas (رضي الله عنه) said: Then the Prophet of Allah (ﷺ) came out, and it is as if I can see him now, with water dripping from his head and putting his hand on the side of his head and saying: "Were it not that it would be too difficult for my ummah, I would have instructed them to pray at this time."