This is one of the harder passages to interpret. I’ve heard several interpretations on it. I’m not sure that the one I have is the correct one and it may change in the future, but for what it’s worth, here it is.
Again, Paul is talking about the contrast between tongues and prophesy and why he prefers to see prophesy in the church rather than tongues. He first says,
Brothers, stop thinking like children. In regard to evil be infants, but in your thinking be adults. (20)
In what way were the Corinthians like children? They were acting like children in that spiritual gifts, particularly the gift of tongues, was like a new toy to them. They played with it, without really thinking about what it was for or what effects it might have on others. All they knew was that they enjoyed “playing” with it, perhaps for the spiritual benefit it gave them in their souls (4), and perhaps for the fleshly benefit of showing off what they could do to unbelievers.
And Paul says, “Hey. With regard to evil, be as innocent as infants. But in the way you think about spiritual gifts and other matters, grow up. Don’t just consider yourself, but consider the unbelievers among you and how your actions affect them.”
How were the Corinthians thinking? This is a guess, but it seems that they thought it actually had a positive effect on unbelievers, possibly because of what happened on Pentecost. But they failed to take into account something very important. There were actually foreigners visiting on Pentecost who could understand what was being said. In their church services, however, there were unbelievers who had no idea what was being said when the Corinthians spoke in tongues. Because of this, they were not impressed by the Corinthians speaking in tongues; rather, they were turned off.
So Paul is saying, “You guys are all speaking in tongues during your services, and you seem to think that unbelievers will be impressed by this gift that you have and come to Christ. But think about what the scripture says.”
Through men of strange tongues and through the lips of foreigners I will speak to this people, but even then they will not listen to me (21).
This is taken from Isaiah 28:11-12. The context is that the people of Israel were considering the words of God as babble. And so God was saying, “Fine, you consider my words babble. I will show you what babble is. You will find yourselves exiled in a land of people whose words to you will truly be babble. And even then you won’t repent.”
Paul then applies this passage in reference to tongues and says, “Don’t you see? Tongues uninterpreted and used in front of unbelievers is indeed meant as a sign for them. (22) But it’s not a sign meant to convert them, but to express judgment on them. They rejected words that they could understand, and so God makes all his words babble to them. The result of this is not that they repent, but that they become even more hardened. And so Paul says,
So if the whole church comes together and everyone speaks in tongues, and some who do not understand or some unbelievers come in, will they not say that you are out of your mind? (23)
Even on Pentecost, you see the unbelieving Jews saying this (Acts 2:13).
Prophesy, on the other hand is a sign for those who (would) believe. (22)
But if an unbeliever or someone who does not understand comes in while everybody is prophesying, he will be convinced by all that he is a sinner and will be judged by all, and the secrets of his heart will be laid bare. So he will fall down and worship God, exclaiming, “God is really among you!” (24-25)
Now, full disclosure here: there is no word “would” before “believe” in verse 22. But it does seem to me that it best explains Paul’s meaning here in context.
So what do we take from this? The Corinthians didn’t rightly understand their gifts and what they were for. As a result, Paul warned that their gifts could have the opposite effect of what they were expecting.
How about you? Do you rightly understand and use your gifts, remembering who and what they are for? If you use them wrongly, whether it be with wrong motivations or in wrong situations, you may be shocked by the results you reap.
The most important thing, though, is to remember that our gifts are not primarily for our benefit or blessing, but to accomplish God’s purposes and to glorify him. How are you using your gifts?