For if I pray in an unknown tongue, my spirit prays, but my understanding is unfruitful.
Therefore let him that speaks in an unknown tongue pray that he may interpret.
Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue.
For he that speaks in an unknown tongue speaks not unto men, but unto God: for no man understands him; but in the spirit he speaks mysteries.