I Corinthians 14:10-15

There are, it may be, so many kinds of languages in the world, and none of them is without significance. Therefore, if I do not know the meaning of the language, I shall be a foreigner to him who speaks, and he who speaks will be a foreigner to me. Even so you, since you are zealous for spiritual gifts, let it be for the edification of the church that you seek to excel. Therefore let him who speaks in a tongue pray that he may interpret. For if I pray in a tongue, my spirit prays, but my understanding is unfruitful. What is the conclusion then? I will pray with the spirit, and I will also pray with the understanding. I will sing with the spirit, and I will also sing with the understanding.