As with all parables, the purpose of the Parable of the Mustard Seed is to teach a concept or “big idea” using various narrative elements or details that are common, easily recognized, and usually representational of something else. While the elements themselves do have importance, an overemphasis on the details or literal focus on an element usually leads to interpretive errors and missing the main point of the parable.
The Parable of the Mustard Seed is a short one: “The kingdom of heaven is like a mustard seed, which a man took and planted in his field. Though it is the smallest of all seeds, yet when it grows, it is the largest of garden plants and becomes a tree, so that the birds come and perch in its branches” (Matthew 13:31–32).
One of the possible practical reasons that Jesus used parables such as this is that, by depicting concepts in word pictures, the message is not readily lost to changes in word usage, technology, cultural context, or the passage of time. Literal, detailed narratives are more susceptible to becoming archaic or obsolescent. Two thousand years later, the imagery is still vivid. We can still understand the concept of a growing seed. Jesus’ parables are brilliant in their simplicity. This storytelling approach also promotes practicing principles rather than inflexible adherence to laws.
The Parable of the Mustard Seed is contained in all three of the Synoptic Gospels (Matthew 13:31–32; Mark 4:30–32; Luke 13:18–19). In this parable, Jesus predicts the amazing growth of the kingdom of heaven. The mustard seed is quite small, but it grows into a large shrub—up to ten feet in height—and Jesus says this is a picture of kingdom growth. The point of the Parable of the Mustard Seed is that something big and blessed—the kingdom of God—had humble beginnings. How significant could the short ministry of Christ be? He had but a handful of followers, He was a man of no rank and without means, and He lived in what everyone considered a backwater region of the world. The life and death of Christ did not catch the world’s attention any more than a mustard seed would lying on the ground by the road. But this was a work of God. What seemed inconsequential at first grew into a movement of worldwide influence, and no one could stop it (see Acts 5:38–39). The influence of the kingdom in this world would be such that everyone associated with it would find a benefit—pictured as the birds perched on the branches of the mature mustard plant.
Elsewhere in Scripture, the kingdom of God is also pictured as a tree. A passage in Ezekiel, for example, parallels the Parable of the Mustard Seed in many ways. In this prophecy, the Lord God promises to plant a shoot “on a high and lofty mountain” (Ezekiel 17:22). This small sprig “will produce branches and bear fruit and become a splendid cedar. Birds of every kind will nest in it; they will find shelter in the shade of its branches” (Ezekiel 17:23). This messianic prophecy foretells the growth of Christ’s kingdom from very small beginnings to a sizable, sheltering place.
Some have wondered why, in the Parable of the Mustard Seed, Jesus calls the mustard seed the “smallest” of seeds and the mature mustard plant the “largest” of plants in the garden, when there were smaller seeds and larger plants. The answer is that Jesus is using rhetorical hyperbole—an exaggeration to make a point. He is not speaking botanically but proverbially. Jesus’ emphasis is on the change of size—from small to large—and the surprising nature of the growth.
The history of the church has shown Jesus’ Parable of the Mustard Seed to be true. The church has experienced an explosive rate of growth through the centuries. It is found worldwide and is a source of sustenance and shelter for all who seek its blessing. In spite of persecution and repeated attempts to stamp it out, the church has flourished. And it’s only a small picture of the ultimate manifestation of the kingdom of God, when Jesus returns to earth to rule and reign from Zion.