There are many levels of understanding the significance of Rosh Hashana also being Rosh Chodesh, a new moon. Every Rosh Chodesh inaugurates an entirely new energy and a new opportunity to begin again. The ability to renew and rejuvenate is one of the secrets of the Jewish calendar being based on the lunar cycle. The capacity to begin again and again lies at the very root of Jewish survival. Rosh Hashana, the new year, is the “headquarters” for newness, thus it shares the same energy as Rosh Chodesh.
The shape of the moon on Rosh Chodesh and Rosh Hashana is but a thin, cup like sliver, seen for a short time in the western sky before going down at sunset. The judgement taking place on Rosh Hashana is similarly very hidden, yet a sliver of the light does reach us. We can envision the shape of the moon representing our heartfelt prayers to create a vessel to receive blessings. God wants to give us so much – the question is do we have vessels to receive it.
The Midrash states that when the moon was created it complained to God that both it and the sun could not wear the same crown. Therefore God made it smaller. A different Midrash states that every Rosh Chodesh God – as it were – brings a guilt offering for making the moon small. Rosh Hashana comes on a Rosh Chodesh in order to teach us that since we should not judge anyone till we stand in their place, God – so to speak – whispers to us that he empathizes with our situation and thus understands our desire for rectification and forgiveness, for He too brings a guilt offering on this day! This parable represents the judgement on Rosh Hashana as one of understanding and compassion.