It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), he says: I saw the Messenger of Allah (peace and blessings be upon him) that he always performed every prayer at its prescribed time, except for these two prayers (Maghrib and Fajr), that he (by delaying the Maghrib prayer) would perform Maghrib and Isha prayers together at Muzdalifah, and on the next day, he would offer the Fajr prayer earlier than its usual time.