First, I should explain that most believers who speak in tongues accept the name Pentecostal because they think this "gift" arose on the day of Pentecost. But if one simply reads through the first two chapters of Acts, one sees that tongues spoken then and there were not unknown or new tongues as manifested by the Pentecostals. They were known tongues, according to which we read:
Acts 2Furthermore, when Peter stood up to explain what was taking place, he interpreted it not as tongues but as prophecy, saying that it was what was spoken by the Prophet Joel:
11. (both Jews and converts to Judaism); Cretans and Arabs--we hear them declaring the wonders of God in our own tongues!
Joel 2This brings us To I Cor. 14:5 in which Paul makes the clear distinction between tongues and prophecy. He accepts both, but the Pentecost event and the prophecy of Joel included only prophecy -- that is, speaking intelligibly. Where did the unknown tongues, or glossolalia come from?
28 And afterward,
I will pour out my Spirit on all people.
Your sons and daughters will prophesy,
your old men will dream dreams,
your young men will see visions.
29 Even on my servants, both men and women,
I will pour out my Spirit in those days.
The Bible does not inform concerning this question, but we need only look to certain primitive religious practices to find an answer. I believe it to be pure emotionalism and that the Holy Spirit has nothing whatever to do with it because the Bible, apart from Paul, does not inform us. It is, of course, easy to find, in practice, in Pentecostal congregations throughout the world today. That Paul acknowledges it is one more of the many reasons for considering him to be a false apostle.
This brings us finally to Mark 16:17. The Greek word is the same as in I Cor. 14, (glossais) but that is irrelevant because Jesus did not utter these words. This verse asserts that believers, in additon to speaking in new tongues, will also take up snakes and, if they drink any deadly thing, it will not hurt them. These "signs" are completely inconsistent with the true utterances of the Lord, who would never urge his disciples to seek or manifest such signs. We have confirmation of this when we see what is the fact, that the oldest manuscripts (from the 4th Century) that include Codex Sinaiticus and Codex Vaticanus do not include the Longer Ending of vss. 9-20. Someone, probably under the influence of Paul, stuck these verses onto the gospel to get authority for their primitive practices. There are two other endings for Mark that have been stuck on through the centuries by scribes who saw, in the seeming incompleteness of this gospel, an opportunity to put their practices and belief's in the mouth of the Lord. These include the Shorter Ending, found in only a few manuscripts, and the Freer Ending that was quoted in Latin by Jerome. It is my view that both Matthew and Luke sufficiently made up what was lacking in Mark, and the Lord said nothing in either of those gospels comparable to Mark 16:17. In any case, Jesus did not prophesy glossolalia as a sign of true believers. I believe that one can read a clear explanation of this phenomena of speaking in tongues, known by Pentecostals as the Second Blessing at this site.
But there is more confirmation from the lips of our Lord Jesus, for he did in fact state what the Holy Spirit would do when he came, and this did not include speaking in tongues. We have this:
We have no authority from the Lord to indow the Holy Spirit with any function that the Lord did not give him. Based on all these things, I can only conclude that glossolalia, or speaking in tongues, is but another aspect of Paulinism that long ago gave shape to the Christian Church.