Wherefore let him that speaketh in an unknown tongue {h} pray that he may interpret.

(h) Pray for the gift of interpretation.

People's New Testament

14:13 Let him that speaketh in an unknown language pray that he may interpret. Let him pray that he may have the gift of interpretation also. See PNT 1Co 12:10. Let him pray that he may understand what he utters, so as to explain it.

Wesley's Notes

14:13 That he may be able to interpret - Which was a distinct gift.

Jamieson-Fausset-Brown Bible Commentary

13. Explain, "Let him who speaketh with a tongue [unknown] in his prayer (or, when praying) strive that he may interpret" [Alford]. This explanation of "pray" is needed by its logical connection with "prayer in an unknown tongue" (1Co 14:14). Though his words be unintelligible to his hearers, let him in them pray that he may obtain the gift of interpreting, which will make them "edifying" to "the church" (1Co 14:12).

Matthew Henry's Concise Commentary

14:6-14 Even an apostle could not edify, unless he spoke so as to be understood by his hearers. To speak words that have no meaning to those who hear them, is but speaking into the air. That cannot answer the end of speaking, which has no meaning; in this case, speaker and hearers are barbarians to each other. All religious services should be so performed in Christian assemblies, that all may join in, and profit by them. Language plain and easy to be understood, is the most proper for public worship, and other religious exercises. Every true follower of Christ will rather desire to do good to others, than to get a name for learning or fine speaking.