Nafi’ narrates from the freed slave (mawla) of Abdullah ibn Umar (may Allah be pleased with them both): Umar ibn al-Khattab (may Allah be pleased with him) wrote to his governors that among all your duties, prayer is the most necessary and important in my view. Whoever learns the rulings and regulations of prayer and offers it at its proper time has safeguarded his religion. Whoever neglects the prayer will neglect other duties even more. Then he wrote: Perform the Zuhr prayer when the sun declines and the shadow is equal to the length of a man’s hand, until the shadow becomes equal to the man himself. And perform the Asr prayer as long as the sun is high and white, such that after the Asr prayer, a man riding a camel could travel six or nine miles before sunset. And perform the Maghrib prayer when the sun sets, and perform the Isha prayer when the twilight disappears, up to one-third of the night. Whoever sleeps before the Isha prayer, may Allah not let his eyes rest, may his eyes not rest, may his eyes not rest. And perform the Fajr prayer while the stars are still clearly visible and shining.