He also said, ‘The kingdom of God is as if someone would scatter seed on the ground, and would sleep and rise night and day, and the seed would sprout and grow, he does not know how. The earth produces of itself, first the stalk, then the head, then the full grain in the head. But when the grain is ripe, at once he goes in with his sickle, because the harvest has come.’ (Mark 4: 26-29)

This parable is unique to Mark. Is this an expansion on the earlier Parable of the Sower?

In the other gospels, more than in Mark, the Kingdom of God is coming, close by, and at hand. Recognizing and receiving the Kingdom of God is a principal theme of Jesus' ministry.

If the human soul is the soil - as in the previous parable - then the seed can be perceived as the apprehension of God's intention.

The soil receives the seed and then, according to this saying, "produces of itself" (kapophoreo automatos). The Greek strongly implies acting on one's own impulse without instigation or intervention.

With our modern understanding of biology this explanation may seem to undervalue the seed, sun and rain. But the parable gives special emphasis to the receptivity and fertility of the soil.

Our apprehension of God's intention emerges gradually - stalk, then head, then ripened grain --- and we do not always understand how this happens.

Our free will - a gift and expression of God - may sow the seed. We must consciously choose to consider God's intention. But our conscious choice, will, and logic can only go so far. It is in our dark, moist, and earthy soul that we fully encounter the reality of God.