This hard-won understanding is contrast with the automatic way in which the seed yields its fruit in nature. If we sow the seed and harvest the crop, God does the rest. This is a free gift from God.
If you didn't know anything about Christ, except his words as captured in the Gospels, you would think that his main mission on earth was to describe the "kingdom of Heaven," which was can also describe as God' reign, the universal rule, or, if I may add another interpretation, God's plan. The vast majority of his parables begin with the words "the universal rule is like." Strangely enough, these parables do not involve the story of sin and redemption central to Christianity. Instead, they are always about learning, growing, and getting our priorities straight.
"Like" is from homoioô (homoioo), which means "to make like," "to become like," "to liken," and "to compare.
"Comparison" is from parabolê (parabole), which means "comparison," "illustration," and "analogy." It is most often translated in the NT as "parable."
"Compare" is from paraballô (paraballo), which means "to throw beside," "to throw to," "to expose," "to set beside," "to set in parallel," "to compare," "to throw, turn, or bend sideways," "to deposit with one," "to deceive," "to come near," "to come alongside," and "to direct one's course toward."