The Heavenly hosts can only perform their assigned tasks. Men, however, are invested with freedom of will, and are capable of altering their tasks for evil to themselves and evil to all the world. When the beauty of Yefet dwells in the tents of Shem, and serves Shem, it is genuine beauty. Strength becomes transformed into brutal tyranny. Wisdom becomes cunning.
Truth becomes distortion.
Three mitzvot alone, however, they wished to annul completely. Shabbat recalls to its adherents, and all who see them, that the world has a ruler, through whose word everything was created. We are lords of the earth and all its inhabitants shall bow only unto us,' said the Greeks. The consecration of the new month recalls to those who consecrate it, and to all who view them, that God's power acts in Time. If the Beit Din fails to sanctify the new month, it remains profane.