Musar zu Bereschit 32:2

This is why he instructed Israel to offer a male goat as a sin offering each New Moon in compensation for having reduced the moon's size (i.e. Israel's size in this world). The Rekanati, in his commentary on Exodus 12,2, explains at length that the function of this sin-offering on the New Moon is very similar to the function of the scapegoat which is tendered to Azzazel on the Day of Atonement. Allegorically speaking, the reduction in size symbolizes the diminution of the forces of holiness due to Adam's sin. This results in the powers we call חיצוניות experiencing an uplift, increased strength. By sacrificing the male goat on the New Moon as a sin-offering to G–d we are symbolically sacrificing the קליפה, the symbol of negative influences which in turn undermines the influence of this קליפה. By doing this we re-convert some of the forces that though they originated in a holy domain had become active as negative forces. Such a positive act results in atonement. Rashi describing Genesis 32,2,1 explains Jacob's motive in sending gifts to Esau with the words: אכפרה פניו, to mean קנוח, "wiping clean." Atonement then is a way of "wiping the slate clean." Sin is considered to be a stain on our soul or character. Atonement is the removal of the stain in question. We follow this procedure every month whenever the moon renews itself. This process will continue until the קליפה has been reduced so much that the moon can regain its former size and its light equals that of the sun. At such a time, when the world will be filled with knowledge of G–d, the physical part of our bodies as well as matter in the universe will be imbued with sanctity similar to that intangible part of man, his soul.

It is related in Zohar Chadash, Parashas Noach (26b): Rabbi Elazar and his father-in-law Rabbi Yose were traveling from Usha to Lud. Rabbi Yose said to Rabbi Elazar, “Did you happen to hear from your father, Rabbi Shimon ben Yochai, what is meant by the verse, ‘And Yaakov went on his way and angels of God met him’ (Bereishis 32:2)? Who were these angels?” “I do not know…,” he replied. While they were yet traveling they noticed a certain cave and heard a voice saying, “There were two fawns of a gazelle that brought Me pleasure. They were the holy camp that met Yaakov and then went before him.” Rabbi Elazar became extremely agitated and fearful. “Master of the Universe!” he said, “Is this Your way? It would have been better had we not heard this, for now that we have heard it we still do not know who they were!” Then a miracle occurred and they heard a voice saying, “They were Avraham and Yitzchak.”