1 Corinthians 14:12 Even so ye, forasmuch as ye are zealous of spiritual gifts, seek that ye may excel to the edifying of the church. 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.
Paul wanted to tell the Corinthians that they should be as zealous about excelling and edifying the church as they were about their pursuit of Spiritual gifts. There is nothing wrong with being “zealous of spiritual gifts” and it is okay for us to desire them if we want them—with one stipulation: we should desire those gifts that “EXCEL to the edifying of the CHURCH.” The edifying of the church should be more important than any gift that is used to edify self. That being the case; no Bible believer should speak in unknown tongues because he is only edifying himself (vs. 4). If he does speak in tongues that no one else who is present knows (vs. 13), then he had better pray that God will let him be bilingual and give him the ability to put it into another language so the listeners can understand. Then he will be edifying the church and not himself.
Paul says that if he prays in an unknown tongue, it is HIS spirit that prays. He is not saying that it is the Holy Spirit that prays, it is HIS spirit, the spirit of man. See that small “s” right in the context? “…my spirit prayeth, but my understanding is unfruitful.”
The Charismatic uses this verse to prove his doctrine of “praying in the spirit.” To a Charismatic, “praying in the spirit” is, “If I pray in an unknown tongue my spirit prays, but I don’t understand what I am saying.” He explains this as the Holy Spirit using him as a conduit to talk to God in a special heavenly prayer language that no one else understands except God. Not even the person speaking it understands what he is saying. However, no Charismatic can explain just why God would need to use a man to talk to Himself?
When Paul says that his “understanding is unfruitful” he means it in the sense that his ability to make OTHERS understand is unfruitful; he is not bearing any fruit among them. When he says “my” understanding, it means that he is taking the responsibility to cause his listeners to understand what he is saying. Paul understands what he is saying, but his lack of speaking in a language that others do not know means that THEY cannot understand what he is saying. Therefore, because the PEOPLE LISTENING TO HIM does not understand what he is saying, the whole process of communication is unfruitful. We know that this is the right interpretation because of Verse 16 and 17. In those two verses, the speaker knows he is giving thanks to God, but the hearer does not.
The Living Bible reads, “For if I pray in a language I don’t understand, my spirit is praying, but I don’t know what I am saying.” All of the rest of the new Bibles follow this private teaching of the Pentecostals, who don’t understand what they are saying when they “speak in tongues.” When you change one word of a King James Bible, you are in danger of losing sound doctrine. So the first rule of Bible interpretation is “DON’T CHANGE WHAT THE BIBLE (AV, 1611) SAYS”—not even one word.