The mission of the early church is found in the words of Jesus in Matthew. To grow people into whatever it is that Jesus wants them to do by immersing them in scripture, the presence of other believers, and discipling each other for spiritual and emotional growth.
In order to fulfill this mission, a church needs to intentionally provide opportunities for worship, teaching the word, developing honest relationships, honest sharing of life.
In Romans 15 Paul says that the people he is writing to, are knowledgeable about things and that they are qualified to instruct and warn one another. Paul is talking about ordinary believers, not ordained people, not trained therapists or counselors. Paul is not talking about the spiritual elite, he is talking about ordinary believers.
Matthew 18 gives details about what a believer should do when another believer sins against them. Every one of us has been sinned against. It is impossible to live in our fallen world and not be sinned against. There is also the sad reality that we each have likely sinned against others. Most people are more aware of how other people have sinned against them than they are of how they may have sinned against someone else.
1 Thessalonians 5 tells us that different people need different types of admonishment or instruction. Seek to understand the motive, the reason, etc. The lazy need to be warned and the faint-hearted need to be encouraged.
Scriptures used – Romans 15:14, Matthew 28:18-20, Matthew 18:15-20, 1 Thessalonians 5:14-15, 2 Thessalonians 3:6-15, Ephesians 4:11-16