The answer is as follows:

As for dawn: the appearance of dawn after pitch darkness is among the signs of Allah for which He deserves to be venerated and thanked. For no one can bring forth this radiant light after pitch darkness except Allah, as He, Exalted is He, says:

“Say, ‘Have you considered: if Allah were to make the night perpetual over you until the Day of Resurrection, what god other than Allah could bring you light?’” [al-Qasas 28:71]

As for noon: the sun’s passage from the eastern side to the western side is likewise among the signs of Allah. No one can move it from one direction to the other except Allah, Exalted is He.

As for the afternoon prayer: no wisdom behind it is apparent to us, but there is no doubt that it has a profound wisdom.

As for the sunset prayer: its wisdom is like that of the dawn prayer, namely, that night is among the tremendous signs of Allah for which He deserves to be thanked and venerated.

The same may be said of the night prayer, for the disappearance of the twilight and the fading of the sun’s effects are likewise among the great signs indicating the perfection of Allah’s power and wisdom.

A Prayer Is Deemed Performed Within Its Time by Catching the Opening Takbīr

His statement: “A prayer is deemed performed within its time by catching the opening takbīr.” The term “prayer” is general and includes both obligatory prayers and time-specific voluntary prayers, such as the mid-morning prayer and the witr prayer, for both have prescribed times. The regular sunnah prayers likewise have prescribed times: the prayers performed before an obligatory prayer begin when that prayer’s time enters and continue until its iqāmah is given, while the prayers performed afterward begin upon the completion of the obligatory prayer and continue until the time expires. Thus, every prayer with a prescribed time is deemed to have been caught by catching the opening takbīr.