The sun set while I was with Abdullah bin Umar, and we traveled on. When we noticed that evening had come, we said, "The prayer."He continued riding until the twilight disappeared and the stars came out. Then he dismounted and prayed both prayers together. Afterward he said, "I saw the Messenger of Allah ﷺ, whenever he was pressed for time on a journey, pray these two prayers in this way," meaning that he would combine them after nightfall.
حدثنا عبد الملك بن شعيب حدثنا ابن وهب عن الليث قال قال ربيعة يعني كتب إليه
غابت الشمس وأنا عند عبد الله بن عمر فسرنا فلما رأيناه قد أمسى قلنا الصلاة فسار حتى غاب الشفق وتصوبت النجوم ثم إنه نزل فصلى الصلاتين جميعا ثم قال رأيت رسول الله ﷺ إذا جد به السير صلى صلاتي هذه يقول يجمع بينهما بعد ليل