36:39 And the moon, We have determined way stations for it, till it returns like the old palm branch.
It has been said that the wisdom in the waxing and waning of the moon is that at the beginning of creation, the moon's light was in perfection. It gazed upon itself and self-admiration appeared in it. The Exalted Lord commanded Gabriel to strike the moon's face with his wing, and that took away the light. Ibn ʿAbbās said, "The lines you see on the face of the moon are the mark of Gabriel's wing."
He took away the light, but the imprint stayed in place. It is the imprint of the words of tawḥīd written on the moon's forehead: "There is no god but God; Muḥammad is God's messenger."
When the light was taken from the moon, it was prevented from serving at the Threshold. The moon asked for help from the angels so that they would intercede for it. They said, "Lord God, the moon has become accustomed to serving at the Exalted Threshold. Is there no way for You not to deprive it totally?"
The Exalted Lord accepted their intercession and commanded it to prostrate itself once a month on the fourteenth night. Now every night when it comes up and the time of service becomes closer, its light increases, until the fourteenth night, the time of prostration, and its light reaches perfection. Then when the fourteenth passes, every night its light diminishes because it is becoming farther from the carpet of service.
It has also been said, "What is similar to the sun is a servant who is forever in the radiance of recognition. He is the possessor of stability, not undergoing variegation. The sun of his recognition shines from the mansions of his felicity constantly. It is not taken by eclipse, nor curtained by clouds.
"What is similar to the moon is a servant whose states are constantly undergoing transition. He is the possessor of variegation. He has an expansion that lifts him up to the boundary of union, and then he is pushed back into lassitude and falls into contraction in the limpidness of his state. Thus he diminishes and returns to deficiency in his affair, until his heart is lifted up from his present moment. Then the Real is munificent toward him and gives him the success to return from his lassitude, bringing him back from his intoxicatedness. His state continues becoming more limpid until he is near to union and he climbs up to the peak of perfection." At that point he says with the tongue of his state,
In Your love I descended to a station
whose descendness bewilders the mind.