Otherwise when you are praising God in the Spirit, how can someone else, who is now put in the position of an inquirer, say “Amen”to your thanksgiving, since they do not know what you are saying? 17 You are giving thanks well enough, but no one else is edified. (I Corinthians 14:16-17 NIV)
In the passage above, Paul continues to emphasize his point that Christians must use clear communication when worshiping God in church services. Paul has already spent many verses establishing this point: so it must be very important. What Paul is saying here is that Christians should not sing or praise God in a supernatural language during a church service unless they have an interpreter. Singing or speaking during a church service should not be made up of pure emotion: it needs to clearly communicate truth in a human language that others can understand. Otherwise, when you are praising God in the Spirit you are pressuring others to say Amen to your thanksgiving, which is wrong, because they do not even know what you are saying. It is possible, if your heart is truly being inspired by God, that you are giving thanks well enough, however, this kind of thanksgiving is not helpful to the church because no one else is edified. Therefore, when Christians meet together in church they must restrict their actions to things which edify each other. The preaching and singing should communicate clear truth in the common language which all can understand.