The Cow - 2:238
Pay attention to the prayers, especially the middle prayer. Stand in prayer, giving yourselves wholly to Allah.
Prayer times are determined by the sun:
The Night Journey/17:78
Observe the prayer from the setting of the sun until the darkness of the night. Observe the Qur´an in the morning. In the morning the Qur´an (recitation) is witnessed.
Prophet Hud/11:114
Observe the prayer at both ends of the day and the close part of the night. The good deeds wipe away the evil deeds. This is an admonition for those who will take admonition.
The Cow/2:238
Pay attention to the prayers, especially the middle prayer. Stand in prayer, giving yourselves wholly to Allah.
Ta-Ha/20:130
Be steadfast in your words, and glorify your Lord before the rising and setting of the sun. Remember at night and at both ends of the day so that you may be happy.