1 Corinthians 14:19-21

Young's Literal Translation

¹⁹ but in an assembly I wish to speak five words through my understanding, that others also I may instruct, rather than myriads of words in an [unknown] tongue.

²⁰ Brethren, become not children in the understanding, but in the evil be ye babes, and in the understanding become ye perfect;

²¹ in the law it hath been written, that, `With other tongues and with other lips I will speak to this people, and not even so will they hear Me, saith the Lord;'