12-13. If you be anxious and desirous for proofs of your spirituality, for the gifts and wonders of the Spirit and its activities, then let this desire for an overflowing measure of it in your hearts end always in the furthering of that great spiritual goal, the aim, as I have said, of all the operations of the Spirit, the building up of the Church, of the infinite body of the Christ.
14. To that end pray and sing, bless and give thanks.
15. If I pray with the mind as well as the Spirit, and sing with understanding as well as ecstasy, and interpret to the mind and consciousness the tongue of the Spirit which I utter, then is that great purpose fulfilled.
16. Then will those who hearken to your blessing and giving of thanks say Amen to it. For the demands of the understanding have been fulfilled.
17. But if you give thanks with spiritual voices only, in a language unknown to those who fill the place of the humble listeners and the congregation, however well you do it, the church is not fulfilled and is not edified.
18. My brethren, this language of the Spirit utters itself richly in me, and in more frequent and fuller tones than in all of you,
19. yet would I rather speak five words with the understanding that can help my brother than ten thousand in a language which he does not know.
20. My brethren, you have become as little children in this world, but be not children in understanding, but children only in evil. This speaking with tongues, you say, is a sign, a miracle.