1 Corinthians 14:6-14

6But now, brethren, if I come to you speaking in tongues, what will I profit you unless I speak to you either by way of 1revelation or of 2knowledge or of 3prophecy or of 4teaching? 7Yet even lifeless things, either flute or harp, in producing a sound, if they do not produce a distinction in the tones, how will it be known what is played on the flute or on the harp? 8For if 5the 6bugle produces an indistinct sound, who will prepare himself for battle? 9So also you, unless you utter by the tongue speech that is clear, how will it be known what is spoken? For you will be 7speaking into the air. 10There are, perhaps, a great many kinds of 8languages in the world, and no kind is without meaning. 11If then I do not know the meaning of the language, I will be to the one who speaks a 910barbarian, and the one who speaks will be a 11barbarian 12to me. 12So also you, since you are zealous of 13spiritual gifts, seek to abound for the 14edification of the church.

13Therefore let one who speaks in a tongue pray that he may interpret. 14For if I pray in a tongue, my spirit prays, but my mind is unfruitful.