Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) says: When the Messenger of Allah (peace and blessings be upon him) would set out on a journey before the sun had declined, he would delay the Zuhr prayer and combine it with Asr; and when he would set out after the sun had declined, he would hasten the Asr prayer and combine it with Zuhr; and when he would set out on a journey before sunset, he would delay the Maghrib prayer and combine it with Isha; and when he would set out after sunset, he would combine Isha with Maghrib.