1 Corinthians 14:16
16 Otherwise, if you give thanks with your spirit, how can anyone in the position of an outsider1 say “Amen” to your thanksgiving when he does not know what you are saying?
1 Corinthians 14:23
23 If, therefore, the whole church comes together and all speak in tongues, and outsiders or unbelievers enter, hwill they not say that you are out of your minds?