Nafi’ (may Allah have mercy on him) says that when Ibn Umar (may Allah be pleased with them both) was in a hurry during travel, he would combine the Maghrib and Isha prayers after the twilight had disappeared, and he used to say that when the Prophet (peace and blessings be upon him) was in a hurry, he would also combine these two prayers.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5163
Hadith Gradingحکم دارالسلام:إسناده صحيح ، خ : 1805 .