Mishkat al-Masabih 616 — The Messenger of Allah ﷺ Used to Shorten

‘Abdallah b. ‘Umar said:We waited one night in expectation of God’s Messenger for the last prayer of the evening, and he came out to us when a third of the night had passed, or later; we did not know whether he had been occupied with family business, or something else. When he came out he said, “You are waiting for a time of prayer for which the followers of no other religion wait, and 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 for prayer had come, and then prayed. Muslim transmitted it.