Translation:

78. Establish regular prayers at the sun's decline till the darkness of the night and the morning prayer and reading: for the prayer and reading in the morning carry their testimony.

Notes (Tafseer)

2275. The Commentators understand here the command for the five daily canonical prayers, viz.: the four from the declination of the sun from the zenith to the fullest darkness of the night, and the early morning prayer, Fajr, which is usually accompanied by a reading of the holy Qur-an. The four afternoon prayers are: Zuhr, immediately after the sun begins to decline in the afternoon; 'Asr, in the late afternoon; Magrib, immediately after sunset; and Isha, after the glow of sunset has disappeared and the full darkness of the night has set in. There is difference of opinion as to the meaning of particular words and phrases, but none as to the general effect of the passage.

2276. The morning prayer is specially singled out for separate mention, because the morning is a "peaceful hour" and special influences act on the soul awaking from the night's rest. Special testimony is borne to the prayers of this hour by the angelic host.