1 Corinthians 14:27

If any man speak in an unknown tongue, let it be by two, or at the most by three, and that by course; and let one interpret.

Cross-reference

1 Corinthians 14:13 instructs the tongue-speaker to pray for interpretation — the very ability needed for the two or three speakers here.

1 Corinthians 12:10 lists interpretation of tongues as a spiritual gift — the same gift required for the order in this verse.