Another kingdom parable is the story of the mustard seed. Jesus said, “The kingdom of heaven is like a mustard seed, which a man took and sowed in his field; and this is smaller than all other seeds; but when it is full grown, it is larger than the garden plants, and becomes a tree, so that the birds of the air come and nest in its branches.” (Mt 13:31-32). Again this illustration may have been designed by Jesus to assure those who had trouble reconciling the tiny beginnings of God’s kingdom ushered in by Christ (a mustard seed is about a millimeter in diameter) with the powerful and explosive revolution they were expecting from their Messiah.
But as it turns out this parable is actually a prophecy that we see coming true throughout the church age to this very day. The kingdom that began at Christ’s first coming essentially started in Acts 1 with a group of 120 people (Acts 1:15). A tiny mustard seed in the big picture of the world’s past and present population. From this mustard seed beginning, the worldwide church has grown incredibly to a number that cannot be counted.
Describing the kingdom of God as becoming a “tree for the birds to nest in” ties it into the Old Testament description of mighty kingdoms (Ez 17:23; 31:6; Dan 4:12). In its currently quiet way, the church has become a mighty kingdom. Its true size will eventually be known at the second coming of Christ. Like the parable of the automatic kingdom, this story should encourage us when our ministry work appears to us the size of a mustard seed. We should not despair at small beginnings, but see our work as a leaf or branch in the growing mustard tree; the universal and growing church of Jesus Christ our Lord.