In the Law1 it is written: "Through men of strange tongues and through the lips of foreigners I will speak to this people, but even then they will not listen to me,"2 says the Lord.
References for 1 Corinthians 14:21
Tongues, then, are a sign, not for believers but for unbelievers; prophecy,3 however, is for believers, not for unbelievers.
References for 1 Corinthians 14:22
So if the whole church comes together and everyone speaks in tongues, and some who do not understand or some unbelievers come in, will they not say that you are out of your mind?4
References for 1 Corinthians 14:23
But if an unbeliever or someone who does not understand comes in while everybody is prophesying, he will be convinced by all that he is a sinner and will be judged by all,
References for 1 Corinthians 14:24
and the secrets5 of his heart will be laid bare. So he will fall down and worship God, exclaiming, "God is really among you!"6
References for 1 Corinthians 14:25
What then shall we say, brothers?7 When you come together, everyone8 has a hymn,9 or a word of instruction,10 a revelation, a tongue11 or an interpretation.12 All of these must be done for the strengthening13 of the church.
References for 1 Corinthians 14:26
If anyone speaks in a tongue, two--or at the most three--should speak, one at a time, and someone must interpret.
If there is no interpreter, the speaker should keep quiet in the church and speak to himself and God.
Two or three prophets14 should speak, and the others should weigh carefully what is said.15
References for 1 Corinthians 14:29
And if a revelation comes to someone who is sitting down, the first speaker should stop.
For you can all prophesy in turn so that everyone may be instructed and encouraged.