1 Corinthians 14:13-19

Wherefore let him that speaketh in a tongue pray that he may interpret. For if I pray in a tongue, my spirit prayeth, but my understanding is unfruitful. What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also. Else if thou bless with the spirit, how shall he that filleth the place of the unlearned say the Amen at thy giving of thanks, seeing he knoweth not what thou sayest? For thou verily givest thanks well, but the other is not edified. I thank God, I speak with tongues more than you all: howbeit in the church I had rather speak five words with my understanding, that I might instruct others also, than ten thousand words in a tongue.