Once when we had been living in Passaic there was a Rosh Yeshiva who was visiting and on a Friday night there was an open question-answer session at someone’s house. I recall that someone asked this R.Y. about the Rashi in our parsha which explains the korban musaf of Rosh Chodesh was a kaparah brought on behalf of Hashem for making the moon smaller than the sun. his person said his kid had asked what that meant and he had no explanation. The RY said he did not know either, to which the person objected that he could not simply tell his child that “Tatte does not know”. The RY dismissed that fear by saying that kids need to know their parents don’t know everything either.
The mussar is nice, but I guess I don’t take “I don’t know” too easily – what can it mean to bring an offering on behalf of G-d so he can have atonement? Does G-d sin?
On David Guttman’s blog he already posted in this same topic based on the Rambam in Moreh. The Rambam writes that we must be especially attentive in focusing on the the New Moon korban as dedicated only to serving Hashem because pagan religions engaged in actual moon worship with sacrificial rituals. While this approach explains the extra use of “LaHashem” in the pasuk as a point of emphasis, it does not really explain the language and imagery of the Midrash.
For a different approach, see the Maharal on this Chazal in the Gur Arye; it is rather lengthy, but has a number of key yesodos in machshava (the RY I guess was not a Maharal fan). This is not exactly what he says, but the idea is that the act of creation by definition introduces a distance between the Creator and the physical world, between giver and receiver. We are not yet ready to live in a physical world while simultaneously experiencing G-d’s complete immanence. This symbolically is the moon’s complaint at the moment of creation that it and the sun cannot share the same crown. Creation necessitates the imperfection (which Maharal proves is the true meaning of the word cheit), of blindness to G-d, a necessary evil because of our limitations.
Our job, through Torah and mitzvos, is to bring together the sun and the moon, to work on breaking that polarity and achieve complete dveikus. Hashem asks that we bring a kaparah on behalf of his cheit – i.e. that we perform avodah to elevate the world so that the inherent imperfection that was built-in for our behalf is no longer necessary. Kaparah is not used here in the sense of atonement (compare with Ya’akov’s message to Eisav – “ulay achaprah panav”) but in the sense of removing limitations; removing our inability (not G-d’s!) to perfect our dveikus.
If you make it through the Maharal, I would also recommend seeing the footnotes in the new edition of Mei haShiloach (Ishbitza) on P’ Shmini regarding the conversation between Aharon and Moshe regarding whether the korban of Rosh Chodesh was burnt or eaten, and see also the Tiferes Shlomo (Radomsker) on P’ Korach regarding the Midrash that the sun and moon came to G-d and said that if He does not stand up for Moshe they will no longer shine – why did they not object by other rebellions?