A common misinterpretation views this verse as endorsing uninterpreted 'angelic' tongues for personal edification or mandatory practice today, ignoring its contextual quotation from Isaiah as a judgment sign to unbelievers and Paul's overall argument for tongues to be interpreted in church settings to build up believers; others wrongly apply it to dismiss all miraculous signs as ineffective for conversion, overlooking the passage's call for orderly worship where prophecy benefits all.
I Corinthians 14:21
King James Version (1769)
21 In the law it is written, With men of other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord.
Paul quotes Isaiah 28:11-12 to support his teaching on spiritual gifts, emphasizing that speaking in tongues—foreign languages—serves as a sign primarily for unbelievers, fulfilling God's promise to communicate with rebellious Israel through unfamiliar tongues, yet even this divine sign fails to produce repentance, highlighting human hardness of heart and the superiority of prophecy, which edifies the church through clear understanding rather than mysterious utterances.