What are the bridges of God? How does the gospel spread from my small group to a lost and dying world?
Donald McGavran wrote about this in 1955. He had observed that two churches in the same neighborhood preaching the same doctrine with pastors from the same seminary would have wildly different results. One church would grow rapidly while the other stalled. Afte extensive research, he wrote:
During the years of research that led to writing The Bridges of God I was constantly impressed by the crucial role played in the expansion of the Christian faith by the relatives of Christians. Again and again, I observed that though Christians are surrounded by thousands of fellow citizens, the Christian faith flows best from relative to relative or close friend to close friend. This was true whatever the nationality or language. It was as true in the heartland of America as in Uganda or the High Andes. — Donald McGavran. Understanding Church Growth (pp. 253-254). Kindle Edition.
The gospel spreads on the bridge of relationships.
There are two applications to this truth. One is to use the existing bridges to share the gospel. Encourage and equip your people to share the gospel with their friends. Pray for lost friends by name in your small group.
But, there is a second application, and that is to strengthen or create relationships between the people in your small group with people on the outside. As Sam Chan says it:
But what we need to do is merge our universes. So when our Christian friends go to the movies, we invite our non-Christian friends along. Or when our non-Christian friends have a barbecue, we bring some of our Christian friends along. Bit by bit, our Christian friends will become friends with our non-Christian friends. We will have merged our universes. — Chan, Sam, and Ed Stetzer. 2020. How to Talk about Jesus (without Being That Guy): Personal Evangelism in a Skeptical World. Grand Rapids, MI: Zondervan.
This topic is explored further in the following video.