Verse 14
For if I pray in an unknown tongue - If my prayers are composed of sentences and sayings taken out of the prophets, etc., and in their own language - my spirit prayeth, my heart is engaged in the work, and my prayers answer all the purpose of prayers to myself; but my understanding is unfruitful to all others, because they do not understand my prayers, and I either do not or cannot interpret them. See the note on 1Cor 14:19.