Sunan Abi Dawud Book 4, Hadith 15
The mu'adhdhin of Ibn Umar said: prayer (i.e. the time of prayer has come). He said: Go ahead. He then alighted before the disappearance. He then offered the night prayer. He then said: When the Messenger of Allah (ﷺ) was in a hurry about something, he would do as I did. Then he travelled and covered a distance of three days' journey on the day.
Abu Dawud said: A similar tradition has been transmitted by Ibn Jabir from Nafi' with the same chain.
The Messenger of Allah (ﷺ) combined the noon and afternoon prayers, and the sunset and night prayers at Medina without any danger and rain. He was asked: What did he intend by it ? He replied: He intended that his community might not fall into hardship.
'Abd Allah b. al-'Ala' narrated on the authority of Nafi' saying: When the twilight was about to disappear, he alighted and combined both (the prayers).