[The Sun: 2] And the moon when it follows it

"And the moon when it follows it" means: it succeeds it. It has been said that this is in regard to its rising and the sun's rising—that is, when its rising follows the sun's rising by appearing from the eastern horizon after the sun has risen. This occurs at the beginning of the month; for when the sun rises from the eastern horizon at the start of the day, the moon rises after it, but it has no brilliance [at that time], so it is seen after the sun sets as a crescent. The appropriateness of swearing by it in this context is that it is a description of the moon at the beginning of its state; just as the forenoon (al-duha) is the youth of the day, so too is the beginning of the month its birth.

It is also said to be in regard to its rising and the sun's setting—that is, when its rising follows the setting of the sun. This occurs on the night of the full moon (al-badr), the fourteenth of the month, for at that time it is in opposition to the sun, and the distance between them is half the celestial cycle. When the sun is in the upper half of the cycle (that which is above our heads), the moon is in the lower half (that which is below our feet). Thus, when the sun sets, the moon rises from the eastern horizon. This is narrated from Qatadah. The statement that it is called badr because its rising precedes the setting of the sun—as if it "hastens" (badara) to it by rising—does not contradict this, for that is based on approximation. The appropriateness of swearing by it here is that this is the time of the manifestation of its power, which befits the glorification of its status.

Ibn Zayd said: It follows it throughout the entire month; in the first half, it follows it in rising, and in the second half, it follows it in setting, as mentioned in the two aforementioned opinions.

It is also said that the meaning is that it follows it in derivation, in that it rises and appears illuminated at the time of the sun's setting, taking from its light. This occurs in the first half of the month, for during that time it takes a portion of light each night, unlike the second half. This is narrated from Ibn Salam and was chosen by al-Zamakhshari.

Al-Hasan and al-Farra' said, as noted in al-Bahr: It follows it at all times, because it receives light from the sun, and therefore follows it for that reason. Some people denied that any of the predecessors (al-salaf) held the view that the light of the moon is derived from the light of the sun, claiming that this was a view held only by astronomers. What has been mentioned [above] is a refutation of them. The proof regarding the fundamental issue is clearer than the sun: it is the variation of its illuminated phases according to its proximity and distance from the sun, along with the disappearance of its light when the earth intervenes between it and the sun. The contention that the variation might be due to the possibility that one of its halves is illuminated while the other is not, and that it rotates on its axis such that each half is gradually revealed—and the contention that the disappearance of light during an eclipse might be due to the intervention of a dense body between us and the moon that we cannot see—is weaker than the spider's web, as is not hidden to any.

Al-Zajjaj and others said: "It follows it" (talaha) means it becomes full and spherical, thus becoming a follower to the sun in circularity and the perfection of light.