The moon rules the night. But does it really? The moon has no light of its own, it merely reflects the light of the sun. Some times the moon is full and shines bright. Sometimes it is so thin you can barely see it. Sometimes it is hidden and not visible at all. It doesn't even come and go at a fixed time. Sometimes it shines a whole night and sometimes it sets very quickly right behind the sun.
The moon has nothing of its own, it is only a tributary of the sun, reflecting its light on the side of the earth that cannot see the hiding sun. The moon represents Klal Yisroel and each individual Yid. The sun represents Hashem. In this world Hashem is in hiding. We don't have our own light, our task is to reflect Hashem's hidden light on the world and make it a brighter place.
As much as we'd love to shine bright all the time, this is not in our control. Sometimes we are afforded the opportunity and resources to do great things and make a tremendous Kiddush Hashem. We also go through tougher periods where we try to stay afloat ourselves and have no opportunity to shine Hashem's light elsewhere. This all depends on Hashem's will and we must accept it happily.
The Moon sings (Tehilim 104:19), "Asa Yarei'ach LiMoadim" the moon is made to shine at unpredictable intervals. "Shemesh Yada Mivo'o", only the sun knows when the moon will shine. The moon doesn't ask, it takes advantage of every opportunity afforded it without question. Either way it sings a happy tune, eagerly awaiting the sun's bright light so that it can light up the darkness of the night.