Rosh Hodesh is the day when the sliver of a new moon first appears, every 28 days. It is also a day of miracles. When we think of miracles, many of us think of Hanukkah-nes Gadol Haya Sham-a great miracle happened there, the words on the dreidle.
And the miracle we think of when we think of Hanukkah, of course, is the miracle of the oil, that lasted eight days. The little flickering eternal flame that refused to die.
However, the miracle of Rosh Hodesh is even greater. Because the moon's light actually does go out! There is a day before the new tiny silver crescent reappears, when it seems as if there is no moon in the sky at all. This was terrifying! In fact, this day became known as Yom Kippur Katan, the little Yom Kippur, and on it, the pious would fast and repent to ward off this omen of darkness.
Then, on Rosh Hodesh, the moon reappeared, Creation out of nothing. This wasn't just a light sustained, as the light of Hanukkah, this is light resurrected. It is the rejuvenation of hope when there is none.