In the name of Allah , the Entirely Merciful, the Especially Merciful.
Allaah has enjoined upon His slaves five prayers throughout the day and night at specific times decreed by the wisdom of Allaah so that the slave may be in contact with his Lord in these prayers throughout all of these times. They are for the heart like water for a tree, given to it time after time, not all in one go and then it stops.
Part of the wisdom behind doing the prayers at these times is so that people will not get bored or find it too difficult, which would happen if they all had to be done at once. Blessed be Allaah, the Wisest of judges.
(From the Introduction to Risaalat Ahkaam Mawaaqeet al-Salaah (Essay on the Rulings on the Times of the Prayers) by Shaykh Muhammad ibn ‘Uthaymeen, may Allaah have mercy on him).
The times of the prayers were mentioned by the Prophet (peace and blessings of Allaah be upon him) in the hadeeth:
“The time for Zuhr is from when the sun has passed its zenith and a man’s shadow is equal in length to his height, until the time for ‘Asr comes. The time for ‘Asr lasts until the sun turns yellow. The time for Maghrib lasts until the twilight has faded. The time for ‘Isha’ lasts until midnight. The time for Subh (Fajr) prayer lasts from the beginning of the pre-dawn so long as the sun has not yet started to rise. When the sun starts to rise then stop praying, for it rises between the two horns of the Shaytaan.”
(Narrated by Muslim, 612).
This hadeeth explains the timings of the five daily prayers.
