Chasidut zu Bereschit 12:19

The Zohar (Emor, 100b) teaches us that the completion of the Divine service on Rosh Hashanah comes fifteen days later with the festival of Succot. On Rosh Hashanah, which falls on the new moon, the light of the moon is covered. Ten days later, on Yom Kippur, the moon is not yet full. This means that on Rosh Hashanah and Yom Kippur the moon is still close to the sun, receiving her light at points closer to the source. This is as it is said (Ibid.): Rabbi Abba sent a question to Rabbi Shimon asking, “When is the union of Knesset Yisrael (the Shekhina) with the Holy King?” He sent back to him, “(As Avraham said of Sarah:) Indeed she is my sister, the daughter of my father, but not the daughter of my mother. And she became my wife.” (Bereshit, 20:12) This is explained: “On the covering of the day of our festival.”⁴⁵²This refers to Rosh Hashanah, when the new moon is still hidden (i.e. “covered.”) (Tehillim, 81:4) On this day the moon is covered… And it illuminates everything with the light of repentance… Come and See! On this day the moon is covered, and does not shine until the tenth of the month, on Yom Kippurim… Why is the name of the day of Atonement voiced in the plural (Kippurim – Atonements)? It is because on this day, two lights shine as one. The upper luminary shines to the lower luminary. And on this day the upper luminary shines, and not from the light of the sun. God established the service for Israel according to the seasons, each time according to its system. Therefore, by Yom Kippur the Divine service has not yet been completed, to unite God’s will with the service of Israel. Since on the tenth of the month the moon is not yet full, therefore the Divine service cannot yet be totally complete. For this reason, the Divine service performed by Israel on Yom Kippur is through restraint and afflictions.⁴⁵³The five afflictions one must perform on Yom Kippur: not eating, not drinking, not washing, not anointing, and not engaging in marital relations. This is evinced in how the moon does not yet fully receive the light of the sun, since it still too close to the source. On Succot, however, when the moon is full, the Divine service is fulfilled through active service, through the joy of the festival and all of its delights.⁴⁵⁴On Succot there are active commandments such as sitting in the succah, waving the four species, and rejoicing in the feasts of the festival. In the days of the Temple there was also the joyous ritual of water libations. Then the Divine service is truly complete. This is as it is written in the Midrash (Kohellet, 4), “Man’s desire is to work and receive the fruits of his labors.” When man receives, he wants to have earned his reward by his own efforts. In this way he doesn’t suffer the shame of receiving an undeserved gift.⁴⁵⁵In other words, on Succot, the moon is the furthest from the sun. Yet precisely for that reason, it shines the brightest. In our terms, it is precisely when a person is furthest from G-d that he has the ability to serve him. And as a result of that service, comes the joy of receiving a hard-earned reward – the opposite of the shame a person feels when he receives a gift that he does not deserve.