1 Corinthians 14:4-11

4He that speaketh in an unknown tongue edifieth himself; but he that prophesieth edifieth the church. 5I would that ye all spoke with tongues, but rather that ye prophesied: for greater is he that prophesieth than he that speaketh with tongues, except he interpret, that the church may receive edifying.

6Now, brethren, if I come to you speaking with tongues, what shall I profit you, except I shall speak to you either by revelation, or by knowledge, or by prophesying, or by doctrine? 7And even things without life giving sound, whether pipe or harp, except they give a distinction in the sounds, how shall it be known what is piped or harped?1 8For if the trumpet shall give an uncertain sound, who shall prepare himself for battle? 9So likewise ye, except ye utter by the tongue words easy to be understood, how shall it be known what is spoken? for ye shall speak into the air.2 10There are, it may be, so many kinds of voices in the world, and none of them is without signification. 11Therefore if I know not the meaning of the voice, I shall be to him that speaketh a barbarian, and he that speaketh shall be a barbarian to me.