Bible Verses About Parables: Seed growing secretly

And he said, `Thus is the reign of God: as if a man may cast the seed on the earth,

and may sleep, and may rise night and day, and the seed spring up and grow, he hath not known how;

for of itself doth the earth bear fruit, first a blade, afterwards an ear, afterwards full corn in the ear;

and whenever the fruit may yield itself, immediately he doth send forth the sickle, because the harvest hath come.'