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
As we have noted before, Jesus, in speaking of the kingdom, does not always explain Himself in elaborate and expansive terms. The metaphor in this passage seems, at first, to be fairly straightforward. A mustard seed is a really small seed, but the thickly-stalked mustard is a shrub that can grow to heights of ten feet or more. The kingdom starts out small and seemingly insignificant. Planted in the right ground, however, this seed grows into a large, strong, substantial plant. That seems clear enough.
We could assume that the "birds of the air" are there simply to illustrate the size and strength of the branches, and that is true, I'm sure. But birds appear quite a bit in Scripture and the connotations aren't always positive. Consider one of the earliest mentions in Genesis 15:11 when the patriarch Abram cuts his covenant with God: And when birds of prey came down on the carcasses, Abram drove them away. Here the vultures and eagles are disrupting or defiling the sacrifice which Abram had dedicated to the Lord in order to establish a covenant. In passages in the Prophets, scavenging birds are seen feeding off the unburied dead as part of the judgment against the rebellious and wicked.
Consider, too, that the devil is referred to in Ephesians 2:2 as "...the prince of the power of the air, the spirit that is now at work in the sons of disobedience...". Perhaps there is a little more to what Christ is telling us. We remember the Parable of the Wheat and the Tares in which the "weeds" are the "sons of the evil one" planted among the sons of the kingdom.
We get a hint of something else, also, in the next verses, Luke 13:20-21: And again He said, “To what shall I compare the kingdom of God? It is like leaven that a woman took and hid in three measures of flour, until it was all leavened.” Most often in Scripture, leaven has a negative implication, graphically illustrating the carnal nature that puffs itself up with vanity and emptiness. Why would the Lord use leaven as a metaphor for the kingdom while warning His disciples elsewhere to "beware of the leaven of the Pharisees", for example?
Human life is not always clear and distinct. Much of existence is continuous rather than discreet. Processes occur. Things develop. We want a revolution, and we end up growing older and becoming patient. The kingdom of God is revolutionary in its concept and implications, but it must deal with human nature. Lewis mentions an idea in The Screwtape Letters that might be called the "law of undulation". Our progress in Christ is rarely linear. We move forward, and we fall back a little. Our new-found courage pushes us into a new realm of fear. Our increased strength causes us to tackle something too big for us. That's just the way it works.
As the kingdom develops into this great, sheltering organism, it offers protection and comfort to all kinds of life, good and bad. Sometimes it grows and spreads by means that are, if not offensive, at least somewhat questionable. Sometimes the pursuit of wicked ends by evil men is turned to God's purposes. No, that's not true. Always, evil intentions are turned to good by God. Like those nesting birds, the self-centered and sinful benefit from the peace and power of the kingdom as it spreads. God's rain falls upon the fields of both the sinner and the saint. He is good all the time.
Evil among us is not going to break down the kingdom. The presence of sinners is not going to prevent the growth and fruitfulness of the children of the kingdom. The rebellious are going to rebel, and they will, from time to time, suffer the consequences of their rebellion. I used to be one of them. Sometimes I think I still might be. I am glad that the saints did not cut me down or drive me away when I wandered in for shelter from the storm.
In that loaf of bread, along with the festering yeast, there is salt — to flavor, to enhance the appetite, and to preserve. Let it rise. In that great tree that has grown up, there are some nasty birds perched in the shade. Some Christians worry about the birds. Some non-Christians can't tell weeds from wheat and think everything is weeds. Or, they think the kingdom is only a cover for the scavengers. But the kingdom has been growing and spreading for the last two thousand years, and more. You can get a mighty tall tree in that length of time, and it is not done yet. There is no need to worry about a few birds. For one thing, we can know neither their purpose nor their end.
In the same way, as the kingdom grows in us, we may run across things that disappoint and seem incongruent in our own hearts, but we should never despair. Chase the birds away, but don't cut down the tree.
