Albert Barnes Commentary 1 Corinthians 14:23

"If therefore the whole church be assembled together and all speak with tongues, and there come in men unlearned or unbelieving, will they not say that ye are mad?" — 1 Corinthians 14:23 (ASV)

Be come together into one place. For public worship.

And all speak with tongues. All speak with a variety of unknown tongues; all speak foreign languages. The idea is that the church would usually speak the same language as the people among whom they lived. If they used foreign languages that were unintelligible to their visitors, it would give the impression that the church was a madhouse.

And there come in those that are unlearned. Those who are unacquainted with foreign languages, and to whom, therefore, what was said would be unintelligible.

Or unbelievers. Pagans or Jews who did not believe in Christ. It is evident from this that such people often attended Christian worship. Curiosity might have led them to it, or the fact that they had relatives among Christians might have caused it.

That ye are mad? They will not understand what is said; it will be a confused jargon; and they will infer that it is the effect of insanity. Even though this practice might not, therefore, be improper in itself, yet a regard for the honor of Christianity should have led them to abstain from using such languages in their worship when it was unnecessary. The apostles were charged, for a similar reason, with being intoxicated .