1 Corinthians 14:13

13 wherefore he who is speaking in an [unknown] tongue -- let him pray that he may interpret;

1 Corinthians 14:13 Meaning and Commentary

1 Corinthians 14:13

Wherefore let him that speaketh in an unknown tongue
The Hebrew, or any other, the gift of speaking with which is bestowed upon him:

pray that he may interpret;
that he may have also the gift of interpretation of tongues; for as has been before hinted, these two gifts were distinct; and a man might have the one, and not the other; a man might speak in an unknown tongue, so as to understand himself, what he said, and be edified, and yet not be capable of translating it at once into the common language of the people; and if he could not do this, he would not excel in his gift to the edification of the church; whereas if he could interpret he would, and therefore, above all things, he should pray to the Father of lights, the giver of every good and perfect gift, that he might be furnished with this also.

1 Corinthians 14:13 In-Context

11 if, then, I do not know the power of the voice, I shall be to him who is speaking a foreigner, and he who is speaking, is to me a foreigner;
12 so also ye, since ye are earnestly desirous of spiritual gifts, for the building up of the assembly seek that ye may abound;
13 wherefore he who is speaking in an [unknown] tongue -- let him pray that he may interpret;
14 for if I pray in an [unknown] tongue, my spirit doth pray, and my understanding is unfruitful.
15 What then is it? I will pray with the spirit, and I will pray also with the understanding; I will sing psalms with the spirit, and I will sing psalms also with the understanding;
Young's Literal Translation is in the public domain.