Paul's instruction about the use of 'tongues' seems to have taken a disproportionate space in his letter. There is a reason. The church was designed to worship the Lord and to make the gospel accessible to unbelievers. But in Corinth the Christians were failing to be a truly functional church. Internal divisions blighted the church with disagreements about apostolic leadership, disrespect at the Lord’s Supper, tolerance of immorality, and other matters. But their attitude to 'speaking in tongues' showed they did not understand why they had been brought together in Christ.
 
By allowing their meetings to be dominated by praise and prayer in 'tongues', they had forgotten the priority of presenting God's Word. They were enjoying God's good gifts but had not thought about how their unintelligible noises might impact unbelievers. They were not thinking about the spiritual plight of new disciples or the unsaved. By contrast, when God's Word is proclaimed in a language which unbelievers can understand, the Holy Spirit applies the truth to their hearts (Acts 2:37). God can use any truth to challenge the unsaved that they are not living in the truth. Like Peter the disciple, they realise that God knows everything about them, and they are convicted of sin (Luke 5:8). Unless people know that they are sinners, they will never want to have a Saviour.
 
The gospel is not a mystery. God's salvation plan was hidden in the Old Testament times, but seven weeks after the resurrection the secret was out (Colossians 1:25-27). The Holy Spirit used the apostles to reveal why Jesus Christ had to die and rise again. That message, in many different known languages, convicted three thousand people of their sin on one day. As they repented the church was born (Acts 2:38-41). They knew the presence of the indwelling Christ. They continued to tell the message, more and more people believed in Jesus and more churches were formed (Acts 4:29-31).
 
As in Corinth, every church risks becoming useless if the believers do not attend to their gospel purpose. Worship without the Word keeps unbelievers in the dark (because we worship Jesus who died and rose again so that sinners might be saved). If we are only glad of our own salvation and have no passion that unbelievers might welcome God's grace we are dysfunctional Christians; and together we become a dysfunctional church. So let us make sure that we use God's good gifts for both the up-building of the church and gospel proclamation to the world (2 Timothy 4:1-5).