1 Corinthians 14:23
If therefore the whole church be come together into one place, and all speak with tongues, and there come in those that are unlearned, or unbelievers, will they not say that ye are mad? If therefore the whole church be come together into one place, and all speak with tongues, and there come in those that are unlearned, or unbelievers, will they not say that ye are mad?
When the whole church comes together into one place and all speak in a way visitors cannot understand, those who are unlearned or unbelieving and come in will say the members are mad. Instead of being convicted and converted, such outsiders judge the unintelligible gathering to be madness. The lesson is that church meetings are not to be conducted in a way that confuses outsiders or unbelievers or makes them feel alienated. They are to be made interesting so that they attract those who come in.