Sunan Abi Dawud Book 4, Hadith 11
On the expedition to Tabuk if the sun had passed the meridian before the apostle of Allah (ﷺ) moved off, he combined the noon and the afternoon prayers; but if he moved off before the sun had passed the meridian, he delayed the noon prayer till he halted for the afternoon prayer. He acted similarly for the sunset prayer; if the sun set before he moved off, he combined the sunset and the night prayers, but if he moved off before sunset, he delayed the sunset prayer till he halted for the night prayer and then combined them.
Abu Dawud said: Hisham b. 'Urwah narrated this tradition from Husain b. 'Abd Allah, from Kuraib on the authority of Ibn 'Abbas from the Prophet (ﷺ) like the tradition narrated by Mufaddal and al-Laith.
Ibn Umar was informed about the death of Safiyyah (the wife of the Prophet) when he was at Mecca. He proceeded till the sun set and the stars shined. He said: When the Prophet (ﷺ) was in a hurry about something while on a journey, he would combine both these prayers. He proceed till twilight had disappeared. He then combined both of them (the prayers).
The Messenger of Allah (ﷺ) never combined the sunset and night prayers while on a journey except once.
Abu Dawud said: This has been narrated by Ayyub from Nafi' from Ibn 'Umar as a statement of Ibn 'Umar. Ibn 'Umar was never seen combining these two prayers except on the night he was informed about the death of Safiyyah. The tradition narrated by Makhul from Nafi' indicates that he (Nafi') saw Ibn 'Umar doing so once or twice.