1 Corinthians 14:20-22

Young's Literal Translation

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;'

²² so that the tongues are for a sign, not to the believing, but to the unbelieving; and the prophesy [is] not for the unbelieving, but for the believing,