1 Corinthians 14:9
9 So with yourselves, if with your tongue you utter speech that is not intelligible, how will anyone know what is said? For you will be bspeaking into the air.
1 Corinthians 14:14
14 For if I pray in a tongue, my spirit prays but my mind is unfruitful.
1 Corinthians 14:19
19 Nevertheless, in church I would rather speak five words with my mind in order to instruct others, than ten thousand words in a tongue.