Allah then exposited on the sign of His ability to the unbelievers of Mecca when they said: " O Muhammad, bring us a clear sign to prove what you are saying " , saying: (Lo! In the creation of the heavens) in that which We created in the heavens of angels, the sun, moon, stars and clouds (and the earth) and in the creation of the earth and what is in it of mountains, seas, trees and beasts (and (in) the difference of night and day) and in the alternation of day and night (are tokens (of His sovereignty)) signs of His divine Oneness (for men of understanding) for those among them who have reasons,