I am wondering if you might help me to understand what’s going on in 1 Cor.14:22 where Paul writes, “Tongues then, are a sign, not for believers, but for unbelievers; prophecy however, is for believers, not for unbelievers”. Then, in the next verse he says, “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?” Now in v.22 he said tongues were a sign for unbelievers, whereas in v.23 he said if everyone in the church speaks in tongues, unbelievers who hear it will think everybody is crazy. This seems to be a contradiction.
Paul’s teaching here confirms two things about the gift of tongues. First, that one important purpose of the gift is to convey the gospel message to an unbelieving visitor who speaks a language unknown to the group. In that way the visitor can know that he or she is receiving a personal message of supernatural origin. He also taught that tongues are to be used sparingly in a group setting (2 or 3 at the most, one at a time) and only when an interpreter is present (1 Cor. 14:27-28). This is so the group can understand the message as well.
And second, it confirms that having a bunch of people all speaking at once in a language unknown to any of them might make them feel good about themselves (1 Cor. 14:4), but it makes them look like a bunch of crazy people to outsiders.