1 Corinthians 14:2, 14
1 Corinthians 14:2 KJV
For he that speaketh in an unknown tongue speaketh not unto men, but unto God: for no man understandeth him; howbeit in the spirit he speaketh mysteries.
1 Corinthians 14:14 KJV
For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.