A mustard seed and a pinch of yeast—no one would expect the kingdom out of these. No one notices a mustard plant growing; we cannot see yeast at work. This is the paradox of Christ’s kingdom, and it is both wisdom and comfort for our faith, brothers and sisters.
When the Lord ushered his people from Egypt to the promised land in the Old Testament, he did so by doing glorious things. Likewise, in Luke 13:10-17, Jesus freed a woman from a disability on the Sabbath, and the congregation that observed this healing recognized that Jesus was performing an “exodus” salvation. Jesus then told the parable of the Mustard Seed and the parable of the Leaven to help the people who had just witnessed this miracle (and us) better understand the true nature of the kingdom of God.
The Mustard Seed and the Kingdom of God
He said therefore, “What is the kingdom of God like? And to what shall I compare it? It is like a grain of mustard seed that a man took and sowed in his garden, and it grew and became a tree, and the birds of the air made nests in its branches.” (Luke 13:18-19)
Jesus anticipated the misconceptions people would have about the kind of redemption and the type of kingdom he was bringing upon them. What is the kingdom of God like? It is glorious, full of wonders, pomp and power, right? Jesus says, “No, it is more like a mustard seed.”
A mustard seed is not very impressive. It is a very mundane and insignificant comparison to the glorious kingdom. Mustard was a common agricultural product that grew quite prolifically. The variety of mustard grown in Palestine was quite like the mustard weed that now grows all around Southern California.
This is the first odd thing about this comparison. A man plants this mustard seed, and it grows into a tree. But mustard seeds don’t grow into trees; they may become tall weeds, but they are not tree-like at all. Thus, Jesus is using hyperbole to make a point—this “tree” is other-worldly.
Indeed, it is a cosmic tree, for all the birds of the heaven dwell in its branches! Jesus takes this line from two passages in the Old Testament, Daniel 4:10-12 and Ezekiel 31:6. The cosmic tree of these Old Testament verses was the one tree whose roots reach down deep into the earth, and its top most branches extend to heaven.
This tree was the link between heaven and earth, and it was a house for every bird, beast, and human. It was the life-giving tree and a picture of the kingdom that encompassed the world and mediated that heavenly life to all things. It was an ideal picture of kingdom life with God.
So Jesus is telling us that this is what his kingdom will become. The tree signifies the new heavens and new earth. The cosmic tree points to the resurrected life of the age to come. This is what Jesus’ kingdom is like, perfectly portrayed by him granting life and liberty from Satan’s power on the Sabbath (Luke 13:10-17).
The people rejoice, saying, “He is doing glorious things.” Jesus says, “You are right, for my kingdom shall grow into the cosmic tree—the new creation of resurrection.” But this is where irony and mystery come in. It starts off as a mustard seed—a puny seed that sprouts into a weed—how is this the kingdom? This humble, unimpressive beginning is contrasted with the glorious and universal end—God’s new creation.