In the law it is written,— In the law, here, means the Old Testament, Isaiah 28:11 where God has been complaining of the unteachable disposition of the Jews. Instead of, with men of other lips, some read, surely in foreign language, and with foreign lips, &c. Most critics refer the words, as they stand in Isaiah, to the Babylonians, who should come and speak to them in a language unintelligible to them; in which sense the phrase is used elsewhere, Deuteronomy 28:49. Jeremiah 5:15. Diodati thinks the meaning is, "Because they would not attend to plain messages, God would speak to them by such as they could not understand:" and then the Apostle's argument will be, "Since God threatens this as a curse, do not voluntarily bring it upon the church, merely to make ostentation of your own gifts." See Luke 24:44.Acts 24.
Related Commentaries of 1 Corinthians 14:21
1 Corinthians 14:21
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.