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 with the people among whom they dwelt; and if they made use of foreign languages which were unintelligible to their visitors, it would leave the impression that the church was a bedlam.
And there come in - those that are “unlearned.” Those that are unacquainted with foreign languages, and to whom, therefore, what was said would be unintelligible.
Or unbelievers - Heathen, or Jews, who did not believe in Christ. It is evident from this that such persons often attended on the worship of Christians. 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 it might not, therefore, be in itself improper, yet a regard to the honor of Christianity should have led them to abstain from the use of such languages in their worship when it was needless. The apostles were charged, from a similar cause, with being intoxicated; see Acts 2:13.