(20) باب الْمُسَافِرِ إِذَا جَدَّ بِهِ السَّيْرُ يُعَجِّلُ إِلَى أَهْلِهِ
Narrated Zaid bin Aslam from his father:
I was with Ibn `Umar on the way to Mecca, and he got the news that Safiya bint Abu Ubaid was seriously ill. So, he hastened his pace, and when the twilight disappeared, he dismounted and offered the Maghrib and `Isha' prayers together. Then he said, "I saw that whenever the Prophet (ﷺ) had to hasten when traveling, he would delay the Maghrib prayer and join them together (i.e. offer the Maghrib and the `Isha prayers together).
Reference: Sahih al-Bukhari 1805
In-book reference: Book 26, Hadith 32
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 27, Hadith 32