Mark 4 contains a parable that is not often discussed, probably because it does not appear in Matthew 13 or among those well-known parables that Luke alone records, like the Parable of the Good Samaritan. The Parable of the Growing Seed is unique to the book of Mark, the most basic of the gospels, perhaps due to it being so simple and its point so self-evident.
The kingdom of God is as if a man should scatter seed on the ground, and should sleep by night and rise by day, and the seed should sprout and grow, he himself does not know how. For the earth yields crops by itself: first the blade, then the head, after that the full grain in the head. But when the grain ripens, immediately he puts in the sickle, because the harvest has come. (Mark 4:26-29)
This parable has obvious similarities to the Parable of the Sower, but it teaches a completely different principle. It is like the parables in Matthew 13 only in that it is a Kingdom parable and that it has a similar form. As a Kingdom parable, it is a metaphoric explanation by Christ about how God's Kingdom works. Jesus tells His disciples in a kind of spiritual code how they should expect the Kingdom of God to function.
We must understand that the Kingdom of God that He is speaking about is not what we normally think of as God's Kingdom, that is, the time after Christ returns in great power to the earth to set up His government. A future aspect certainly exists in the Kingdom parables, but in most of them, He specifically refers to the present reality of God's church and its future until the return of Christ. Recall that Paul writes in Colossians 1:13 that we have already been "conveyed into the kingdom of the Son of His love." Spiritually, then, we, as members of His church, are already under the dominion, reign, and rule of God. We have been called out of this world (I Peter 2:9) and given citizenship in God's realm (Philippians 3:20).
Kingdom parables show generally how the true church and true Christianity operate in this world. When He brings the Kingdom in its fullness in the Millennium, Christ will deal with matters much differently. His instructions in these parables, however, are to help us in our current, physical lives, not later, for how helpful would they be if they spoke only of things that will occur after the resurrection? As part of Christ's instruction to His disciples, these parables describe how God's Kingdom—in its present, spiritual manifestation—and its citizens function among men on the earth.
In this parable, therefore, Jesus uses the natural process of plant growth to explain how those whom God calls develop spiritually in this world. The process is quite simple, paralleling the growth of a seed into a full-grown, food-producing plant. Just like the growth of a plant, it happens invisibly and somewhat mysteriously too.
Since the Enlightenment, science has taken much of the mystery out of agriculture. We understand a great deal more about how it works than the people of the first-century church did. They would sow seed in their fields, the rains would come, and they would wait. In a few days, they would see sprouts coming up—a miracle! It was just as miraculous to think that the sprout would develop and not only produce another seed, but many other seeds, a great crop.
Jesus says that one becomes spiritually mature in a similar way; the spiritual process contains many parallels. For instance, He says that the sower sows the seed and goes his way, sleeping and rising, watching how things are going, but he really does not know how these things work. He knows that they happen, and he trusts that they will.
This brings out the fact that the sower in this parable is not Christ but a human. Notice that He does not say, "The Sower goes out to scatter seed," but "A man goes out." In other places, especially Matthew 13, He is specific about who the Sower is, but here it is general, a man. If it were Christ, it could not be said that He does not know how they grow. No, this sower is a man whom God uses to sow the seed. He scatters the seed and then goes about his other tasks.
Soon, the seed sprouts due to the resources that God provides; at a certain time, He supplies the light, warmth, water, and nutrients, and the seed germinates. The sower does little more than cast the seed. All that the sower—a minister—does is to speak a word, write an article, or preach a sermon. The recipient is attracted by it, but it is God who does the bulk of the work.
Ministers are not aware of all the ways that God is working behind the scenes to bring a person to the knowledge of the truth. They understand that He does it but not the mechanics of how He opens an individual's mind, turns him to the truth, and allows him to begin to accept His way of life. Ministers, like the sower, just go to bed at night and get up the next morning to continue to do His work. God does the rest, working behind the scenes. He is the Prime Mover, working invisibly and mysteriously to bring forth a productive "plant."
His work goes far beyond just helping the plant to sprout, for He also wants to see, as Jesus says, ". . . the head, after that the full grain in the head" (Mark 4:28). He is looking forward to the fully developed plant, along with ripened, finished fruit—spiritual maturity.
A Christian develops spiritually in the same way as we see in this analogy. God will use whatever method He chooses to get a person's attention. It might be something insignificant that we might not think would catch anybody's eye, but in God's hand, it is sufficient to lead the individual to the truth.
That is just the beginning. God continues to work with him in ways that are beyond human discernment. A minister can be highly instrumental in feeding and cultivating the individual, but he cannot see the invisible, spiritual ways that God is developing that person for His Kingdom. He may have a long experience in the churches of God, but it is not necessarily the case that a minister will be able to see someone's spiritual growth in detail.
In the same way as the plant's growth is described in the parable, a minister may be able to see major changes, but they are crude gauges of all the development that is taking place. He cannot discern each individual's efforts to grow. This is what Christ is suggesting: Growth is taking place despite it being unseen.
If a person inspects his plantings each day, he will see almost no growth from the day before, but if one waits a few days or week between inspections, it is amazing how much they have grown! Similarly, each Christian grows in stages and at a slow enough pace that it can seem like no growth at all. But God is working, and He is aware of the growth—and that should be very encouraging.