Zaib b. Thabit said that God’s Messenger used to pray the noon prayer in the extreme heat, observing no prayer more severe to his companions than it. Then was revealed, “And observe carefully the prayers and the middle prayer”; (Al-Qur’an, 2:238) and he said, “Before it there are two times of prayer and after it there are two times of prayer.”
Concerning God’s words, “The recitation of the dawn is witnessed,” (Al-Qur’an, 17:78). Abu Huraira quoted the Prophet as saying, "The angels of the night and the angels of the day are present at it.”