19. Nevertheless, in public worship, I would rather say five words with my understanding and intelligently in order to instruct others, than ten thousand words in a [strange] tongue (language).
20. Brethren, do not be children [immature] in your thinking; continue to be babes in [matters of] evil, but in your minds be mature [men].
21. It is written in the Law, By men of strange languages and by the lips of foreigners will I speak to this people, and not even then will they listen to Me, says the Lord. [Isa. 28:11, 12.]
22. Thus [unknown] tongues are meant for a [supernatural] sign, not for believers but for unbelievers [on the point of believing], while prophecy (inspired preaching and teaching, interpreting the divine will and purpose) is not for unbelievers [on the point of believing] but for believers.
23. Therefore, if the whole church assembles and all of you speak in [unknown] tongues, and the ungifted and uninitiated or unbelievers come in, will they not say that you are demented?
24. But if all prophesy [giving inspired testimony and interpreting the divine will and purpose] and an unbeliever or untaught outsider comes in, he is told of his sin and reproved and convicted and convinced by all, and his defects and needs are examined (estimated, determined) and he is called to account by all,
25. The secrets of his heart are laid bare; and so, falling on [his] face, he will worship God, declaring that God is among you in very truth.