The Corinthian Church had a problem with speaking in tongues. Their speech was revealing what they were following. They were following after things that promoted themselves. They were twisting God’s Word to make it seem like they were “spiritual.” They all had their own interpretation of the Scriptures and they were imitating “spiritual gifts.” Chapter 14 identifies the selfishness of speaking in tongues in contrast to the selflessness of ensuring others understand what is being said. Chapter 14 identifies how speaking in “tongues” edifies self while prophesy edifies others. It identifies the lack of communication associated with tongues as “madness” and identifies the richness of communication with decency and order.
 Matthew 15:18 But those things which proceed out of the mouth come forth from the heart; and they defile the man.