1 Corinthians 14:13-15 King James Version (KJV)
13 Wherefore let him that speaketh in an unknown tongue pray that he may interpret.
14 For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.
15 What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.