Sahih al-Bukhari — Shortening the Prayers (At-Taqseer) — Hadith No: 1092
Translation
Narrated `Abdullah bin `Umar:"I saw Allah's Messenger (ﷺ) delaying the Maghrib prayer till he offered it along with the `Isha' prayer whenever he was in a hurry during the journey." Salim narrated, "Ibn `Umar used to do the same whenever he was in a hurry during the journey." And Salim added, "Ibn `Umar used to pray the Maghrib and `Isha' prayers together in Al-Muzdalifa." Salim said, "Ibn `Umar delayed the Maghrib prayer because at that time he heard the news of the death of his wife Safiya bint Abi `Ubaid. I said to him, 'The prayer (is due).' He said, 'Go on.' Again I said, 'The prayer (is due).' He said, 'Go on,' till we covered two or three miles. Then he got down, prayed and said, 'I saw the Prophet (ﷺ) praying in this way, whenever he was in a hurry during the journey.' `Abdullah (bin `Umar) added, "Whenever the Prophet was in a hurry, he used to delay the Maghrib prayer and then offer three rak`at (of the Maghrib) and perform Taslim, and after waiting for a short while, Iqama used to be pronounced for the `Isha' prayer when he would offer two rak`at and perform Taslim. He would never offer any optional prayer till the middle of the night (when he used to pray the Tahajjud)