Sahih al-Bukhari 570, 571

It is related from 'Abdullah ibn 'Umar, "One night the Messenger of Allah, may Allah bless him and grant him peace, was kept from us by some business and delayed the prayer to the point that we went to sleep in the mosque and then woke up and then went to sleep and woke up again. Then the Prophet, may Allah bless him and grant him peace, came out to us and then said, "No people on the earth would have waited for the prayer except you.'" Ibn 'Umar did not mind advancing or delaying the prayer when he was not afraid that sleep would overcome him and keep him from praying it in its time. He used to lie down before it. Ibn Jurayj said, "I spoke to 'Ata' and he said, 'I heard Ibn 'Abbas, say, "One night the Messenger of Allah, may Allah bless him and grant him peace, delayed 'Isha' until the people had gone to sleep and woken up, and then gone to sleep and woken up again. 'Umar got up and said, "The prayer!"' 'Ata' said that Ibn 'Abbas said, 'The Prophet of Allah, may Allah bless him and grant him peace, came out - and it is as if I could see him him now - with water dripping from his head - and, placing his hand on his head, he said, "If it were not hard for my community, I would have commanded them to pray it at this time."' I asked 'Ata' to confirm how the Prophet, may Allah bless him and grant him peace, had placed his hand on his head as he had been told by Ibn 'Abbas. 'Ata' separated his fingers slightly for me and then placed the tips of his fingers on the side of his head with his thumb touching the top of his ear by his face between the temple and the top of the beard. He did it neither slowly nor quickly but like that. He said, 'If it were not hard for my community, I would have commanded them to pray at this time.'" XXIV CHAPTER: The time of 'Isha' extends up until the middle of the night Abu Barza said, "The Prophet, may Allah bless him and grant him peace, used to prefer to delay it."