Surah 36. Yasin, Ayah 40

Lit., "nor does the night outrun [or "outstrip"] the day".

 The moon completes a cycle every month (waxing and waning), while the sun takes a whole year to complete its cycle (resulting in the spring, summer, fall, and winter seasons).

Though the sun and the moon both traverse the belt of the Zodiac, and their motions are different, they never catch up each other. When the sun and the moon are on the same side and on a line with the earth there is a solar eclipse, and when on opposite side in a line, there is a lunar eclipse, but there is no clash. Their Laws are fixed by Allah, and form the subject of study in astronomy. Similarly Night and Day follow each other, but being opposites cannot coincide, a fit emblem of the opposition of Good and Evil, Truth and Falsehood: see also n. 3982 above.

Cf. xxi. 33, and n. 2695. How beautifully the rounded courses of the planets and heavenly bodies are described, "swimming" through space, with perfectly smooth motion! As Shakespeare expresses it, each "in his motion like an angel sings, Still quiring to the young-eyed cherubims!"