1 Corinthians 14:6-14

6Now, believers, if I come to you speaking in unknown tongues, how will I benefit you unless I also speak to you [clearly] either by revelation [revealing God’s mystery], or by knowledge [teaching about God], or by prophecy [foretelling the future, speaking a new message from God to the people], or by instruction [teaching precepts that develop spiritual maturity]?

7Yet even lifeless things, whether flute or harp, when producing a sound, if they do not produce distinct [musical] tones, how will anyone [listening] know what is piped or played?

8And if the [war] bugle produces an indistinct sound, who will prepare himself for battle?

9So it is with you, if you speak words [in an unknown tongue] that are not intelligible and clear, how will anyone understand what you are saying? You will be talking into the air [wasting your breath]!

10There are, I suppose, a great many kinds of languages in the world [unknown to us], and none is lacking in meaning.

11But if I do not know the meaning of the language, I will [appear to] be a foreigner to the one who is speaking [since he knows exactly what he is saying], and the one who is speaking will [appear to] be a foreigner to me.

12So it is with you, since you are so very eager to have spiritual gifts and manifestations of the Spirit, strive to excel in ways that will build up the church [spiritually].

13Therefore let one who speaks in a tongue pray that he may [be gifted to] translate or explain [what he says].

14For if I pray in a tongue, my spirit prays, but my mind is unproductive [because it does not understand what my spirit is praying].