30 And he said, Whereunto shall we liken the kingdom of God? or with what comparison shall we compare it? 31 It is like a grain of mustard seed, which, when it is sown in the earth, is less than all the seeds that be in the earth: 32 But when it is sown, it groweth up, and becometh greater than all herbs, and shooteth out great branches; so that the fowls of the air may lodge under the shadow of it. 33 And with many such parables spake he the word unto them, as they were able to hear it. 34 But without a parable spake he not unto them: and when they were alone, he expounded all things to his disciples. (Mark 4:30-34 KJV)
The Parable of the Mustard Seed
The work of grace starts small but becomes great and significant (Mark 4:30-32). “What shall we compare the kingdom of God to?” Jesus asks. “What illustration shall we use?” He doesn’t choose grand comparisons, but something simple and familiar—a mustard seed. This shows that the beginnings of the gospel kingdom would be very small. When the church was first planted, it fit in one room—just 120 people (Acts 1:15), as Israel entered Egypt with only 70 souls. The work of grace in the soul also starts as a tiny thing—a cloud no bigger than a man’s hand. Great things were undertaken by a small group—the apostles discipling the nations—leading to great glory. “Who has begotten me these?”
But the growth will be tremendous. When grown, it is larger than all garden plants. The gospel will spread to the farthest nations and continue through all ages. The church has spread far and wide, producing strong and fruitful branches. The work of grace in the soul brings great fruit even now, but what will it be when perfected in heaven? The difference between a mustard seed and a great tree is nothing compared to the difference between a new believer and a glorified saint (John 12:24).
After describing these parables, the writer gives a general account of Jesus’ preaching. With many similar parables, He taught the people the Word (Mark 4:33), likely pointing us to Matthew 13 for more details. He used parables they could understand, drawing on familiar things and using plain speech to meet them where they were. Though He didn’t explain the mysteries to the crowd, His teaching was clear enough that they could later remember and benefit from it.
But for the time being, He did not speak to them without a parable (Mark 4:34). The glory of the Lord was hidden in a cloud, and God speaks to us in human language so that, gradually, we may understand Him. The disciples later understood sayings they hadn’t grasped at first. Jesus explained these parables to them when they were alone. We wish we had those explanations, like we do for the parable of the sower, but they weren’t necessary—because as the church grew, its experience would explain the parables to us without further comment.