In the first parable of the mustard seed, Jesus points to the inevitability of the growth of the size of the Kingdom of God. Though it may start small like a mustard seed, it will grow relentlessly to become such a large tree that even birds of the air can build their nests on its branches. In the second parable of the leaven (yeast), Jesus points to the inevitability of the growth of the influence of the Kingdom of God, like the yeast, spreading itself into the whole dough and causing the bread to expand when heated.
But what is the Kingdom of God? Jesus has proclaimed and demonstrated the Kingdom's presence and power through the signs He performed. On one occasion, after He had driven out demons from a blind and deaf person, Jesus said, "But if I drive out demons by the Spirit of God, then the kingdom of God has come upon you" (Mt 12:28). Here Jesus is associating the presence and power of the Spirit with the Kingdom of God. In Acts 1:3-5, after spending 40 days with the disciples teaching about the Kingdom of God, Jesus commanded them not to leave Jerusalem but to "wait for the promise of the Father, which, he said, "you heard from me; for John baptized with water, but you will be baptized with the Holy Spirit not many days from now." Again, we see the close association of the Kingdom of God with the Spirit of God. When the Spirit came on the Day of Pentecost, the church came into being and it grew rapidly, transforming whole communities and cities "in Jerusalem and in all Judea and Samaria, and to the end of the earth." It not only grows in numbers but also in influence as it transforms whole societies wherever the Gospel of the Kingdom is accepted.
However, we must make a distinction between church growth and kingdom growth. A local church can grow in size by attracting Christians from other churches. That church grows at the expense of other churches, so there is in fact no net growth in the kingdom of God. Churches that seek to grow by drawing Christians away from their churches are not Kingdom churches because they are neither contributing to the growth of size nor the influence of the Kingdom in the society.
But kingdom-focused churches grow at the expense of Satan's kingdom, rescuing the captives of the devil and delivering them out of their spiritual, psychological and physical bondage. I cannot rejoice when a church grows at the expense of other churches because I can feel the sorrow and pain of the pastors who are losing their members to these "growing" churches. But I rejoice when churches grow at the expense of Satan's kingdom because such churches are Kingdom churches that Jesus speaks about in today's parables.
So, my advice to pastors and Christians is to stop asking Christians from other churches to join their churches. Maybe it's okay to attend services for edification, but Christians should be encouraged to seek the welfare and growth of God's Kingdom through their own congregation. Having seen Christians in smaller churches rise up to the challenge of proclaiming the Gospel of the Kingdom through Alpha and experiencing great joy at seeing Satan's kingdom plundered and many pre-believers set free from their addictions and being empowered by the Spirit, I'm absolutely convinced that any church can experience Kingdom growth -- provided they are Kingdom-minded and lost-focused. The Devil's "Market" is still open for grabs -- and there are not many competitors in this market.
Father, put in us a Kingdom vision and a compassion for the lost who are still enslaved in the Devil's market. Help us grow Your Kingdom by plundering the Devil's slave market, not plundering other congregations. Amen.