The Rabbi taught us, "The malchut shamayim [kingdom of heaven] is like a man who casts seed upon the soil; and he goes to bed at night and gets up by day, and the seed sprouts and grows. How? He himself does not know. The soil produces crops by itself; first the blade, then the head, then the mature grain in the head. But when the crop permits, he immediately puts in the sickle, because the harvest has come."