Abu Dawood: Hadith 420

We remained one night waiting for the Messenger of Allah (ﷺ) to offer the Isha prayer. He came out to us when one-third of the night has passed or even after it. We did not know whether anything kept him occupied or there was some other matter. When he came out, he said: Are you waiting for this prayer ? Were it not that it would impose a burden on my people, I would normally pray with them at this time. He then gave orders to the mu'adhdhin who declared that the time of the prayer had come.