Ingrown toenails are painful. They make it difficult to walk and wear shoes.
There is also such a thing as an ingrown gospel, and it is just as painful.
The gospel, by its very nature, demands input from outside and demands to be put out in culture. If your gospel is not taking you out into the world to love, serve, and befriend those who would not “fit” in your church, and if you never allow someone from the outside to criticize or challenge your life, or your church, you have an ingrown gospel.
And if you are never taking the gospel into other cultures, settings, and situations to see how the gospel both transforms and redeems that culture, and is itself transformed by the culture, you have an ingrown gospel.
For many Christians, the gospel is only about their own salvation. They know they are saved because they have believed in Jesus for eternal life, and while they wait to get swept up into heaven at death or the rapture, they sit around with painted smiles, singing hymns and attending church. Such a life is not a gospel life. This is not being a gospel light, but gospel lite. If the light is the gospel, the church has become a basket, not to carry it in, but to hide it from the world (see Matt 5:15).
The first step to correcting an ingrown gospel is similar to correcting an ingrown toenail. You gotta dig it out, which can be painful. One way to dig out the gospel is to invite input from the outside. We must invite criticism. Painful, harsh, criticism. Allow it to be anonymous even, if that will make it more honest. I know churches that actually pay atheists and people of other religions to attend their church and write a critical report of their visit. Maybe you could bring in Christians from another church tradition or from the other side of the world to come and find fault with how your church is accomplishing (or not accomplishing) your mission.
Once the criticism is received, we must not respond angrily in self-defense, but must move outside our borders, and take the gospel to others. We must bless, love, serve, encourage, heal, and restore.
This entire process is seen in Luke 4:18-30. Jesus taught the gospel in 4:18-21. He then corrected the people on how they were not accomplishing it (4:23-27). The goal, of course, was to challenge them to become participants with Him in being a blessing to the world (cf. Bailey 2008:166). Instead, they tried to kill Him (4:28-30).
How do we respond to critics? Could it be that they are right? Has it ever occurred to us that the voice of the critics may actually be the voice of Jesus?