Mukhtasar Muslim

`Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) says that` I always saw the Messenger of Allah (peace and blessings of Allah be upon him) performing the prayer at its (prescribed) time except for two prayers. One was Maghrib and 'Isha, which he combined and performed at Muzdalifah, and (the second) was the Fajr prayer on its morning, which he performed before its (usual) time.