Here’s the Rebbe’s explanation:
– The idea of Rosh Chodesh is renewal and addition to the regular order of conduct.
As we know the weekly cycle is associated with the sun:
“… and it was evening, and it was morning” (Bereshit, 1:5).
The sun shines daily without change. This symbolises a regular way of living and serving HaShem – « tmidim k’sidram » (constantly, according to one’s custom and order).
In contrast, the moon goes through phases. On Rosh Chodesh, there begins a constant process of growth until on the fifteenth, the moon shines in its fullness. This symbolises a miraculous order of conduct – “musafim ke-hilchatam” (adding up to one’s regular activities, reaching out to a loftier spiritual level). Thus Rosh Chodesh reflects an addition above the normal order of Divine influence.
This miraculous order of conduct can influence our daily lives – up to the point when the natural and the supernatural fuse together, becoming a new permanent dimension of our lives.
Based on the Rebbe’s talk on Shabbat Parshat Vayikra, Rosh Chodesh Nissan, 5751 (1991).
