Shared ground

Paul’s main contrast is about public speech that outsiders can understand versus speech they cannot. He frames it as “mature thinking”: not treating the gathered meeting as a place to display impressive experiences, but as a place where speech should have responsible, understandable effects on others (v.20, v.23–25).

He supports this with a Scripture quote about God speaking through “strange languages” and “strangers,” yet the people still refusing to listen (v.21). On that basis, he says tongues function as a “sign” for unbelievers, while prophecy functions as a “sign” for believers (v.22). Then he shows how, in practice, a room full of tongues can make visitors conclude the group is out of control, while prophecy can expose a visitor’s inner life and lead to recognition that God is present (v.23–25).

Where interpretation differs

1) What “sign” means in v.22. Some read “sign” as mainly negative: tongues signal judgment or distance for unbelievers, matching the Scripture quote about not listening. Others read “sign” as potentially positive or mixed: tongues can function as a marker of God’s activity, but without interpretation it commonly fails to persuade and instead produces the “you’re crazy” reaction Paul describes.

2) How v.22 fits with v.23. One view says v.23 shows that tongues as a “sign for unbelievers” can mean a sign that hardens or repels rather than converts. Another view says Paul is speaking more loosely in v.22, and v.23 clarifies that, in ordinary mixed-company gatherings, uninterpreted tongues do not serve unbelievers well.

3) Who “the unlearned” are. Some think “unlearned” means people unfamiliar with the gift-practice (insiders who lack that experience). Others think it means people without instruction in Christian teaching or Scripture (close to “outsiders,” though not identical). Paul pairs “unlearned or unbelieving” as two categories who can misread what is happening (v.23–24).

Why the disagreement exists

Paul uses a Scripture warning about foreign speech and refusal to listen (v.21), then immediately says tongues are a sign “for unbelievers” (v.22), yet his scenario shows unbelievers reacting badly to tongues (v.23). Readers differ on whether that tension is resolved by taking “sign” negatively, or by treating the statement in v.22 as general while v.23–25 gives the more concrete, practical outcome in a typical meeting.

What this passage clearly contributes

• Public speech in the assembly has an outward-facing effect; visitors’ conclusions matter in Paul’s reasoning (v.23, v.25).
• Paul expects the meeting to include nonmembers and people with limited understanding, and he weighs gifts in terms of what they communicate to them (v.23–25).
• Prophecy, as Paul describes it here, is intelligible speech that can confront, evaluate, and disclose the heart, producing reverence and acknowledgment of God’s presence (v.24–25; compare 1 Corinthians 14:3).
• Tongues without interpretation are likely to be misunderstood in public, regardless of their spiritual value to the speaker (v.23).