CLAIM: Paul writes, “Tongues are for a sign, not to those who believe but to unbelievers” (1 Cor. 14:22). However, usually when non-Christians see Christians speaking in tongues, this seems bizarre, and it pushes them away from Christianity. Why does Paul write this?
RESPONSE: Paul is not saying that we should speak in tongues in front of non-Christians to lead them to Christ. In fact, if you read this passage in its context, you’ll see that he never commands this at all. Instead, he merely says that tongues are a “sign.” In the very next verse, he writes, “Therefore if the whole church assembles together and all speak in tongues, and ungifted men or unbelievers enter, will they not say that you are mad?” (1 Cor. 14:23) Paul goes on to write that prophesy actually brings conviction to non-Christians—not tongues (v.24-25).
What then does Paul mean when he calls tongues a “sign” for non-Christians? Whatever Paul means, he is not thinking about evangelism, as we’ve already seen. Instead, he believes that this is a negative sign for unbelievers—not a positive one. Grudem writes,
Here Paul uses the word “sign” to mean “sign of God’s attitude” (whether positive or negative). Tongues that are not understood by outsiders are certainly a negative sign—a sign of judgment. Therefore Paul cautions the Corinthians not to give such a sign to outsiders who come in. He tells them if an outsider comes in and hears only unintelligible speech, he will certainly not be saved but will conclude that the Corinthians are mad, and the uninterpreted tongues will in his case function as a sign of God’s judgment.
Likewise, Carson writes,
Tongues are a sign for unbelievers. But if you examine how the Scriptures describe the relationship between unbelievers and ‘strange’ (i.e., foreign and unknown) tongues, you discover that they constitute a negative sign. They are a sign of God’s commitment to bring judgment.
Some object that this view would cause the word “sign” to be used in two different ways in this verse—both positively and negatively. But the Greek word “sign” (semeion) doesn’t have any description to it; it simply refers to God’s attitude, whether good or bad. Carson writes, “Many signs are simultaneously negative and positive: negative to the rebellious and unbelieving, and positive to the Lord’s faithful people (e.g. the signs and wonders at the time of the exodus were negative to Pharaoh and to the Egyptians).”
This interpretation fits with the context of this chapter (specifically verse 23), and it also fits with the OT citation of Isaiah 28 (cf. 1 Cor. 14:21).
 Grudem, Wayne. Systematic Theology. Grand Rapids, MI. Zondervan Publishing House. 1994. 1075.
 Carson, D. A. Showing the Spirit: A Theological Exposition of 1 Corinthians 12-14. Grand Rapids, MI: Baker Book House, 1987. 114.
 Carson, D. A. Showing the Spirit: A Theological Exposition of 1 Corinthians 12-14. Grand Rapids, MI: Baker Book House, 1987. 115.