Paul begins his letter to the Corinthians by identifying himself, and Sosthenes. He identifies himself as an apostle, a messenger, of Jesus Christ.
He brought the gospel to them. He was commissioned, and entrusted, by Jesus, not only to bring the message, and begin the church, but also to define the limits of life in the church, because they were given to him by Jesus.
We are all to bring the gospel. We are all to be involved in planting, and establishing, churches. But we are not all given authority to define what life in the church should be like. (Now, I do not mean whether or not we should sing 3 or 4 hymns. Or how long the message should be.) Rather Jesus defines the church as a community. And he defines how his body should live as individuals, and as a community. And he has given messengers, and the scripture, to communicate those definitions. Current day leaders are to take those definitions, clarify them, and help apply them.
Paul, also, mentions Sosthenes. He does not say who Sosthenes is, because everyone in Corinth should know him, as one of their local leaders.
If you have read 1st Corinthians, you realize that the church has gotten pretty messed up. This letter is Paul trying to get the church back on the right track. So, it seems like Sosthenes, seeing things go from bad to worse, tracks Paul down, and informs him about what is going on. So, Paul mentions Sosthenes to let the church know that he is not inventing all of the stuff he is about to say. He has an eye witness, who he trusts, and who they all know.
The Bible encourages all the followers of Jesus to give one another positive instruction, and encouragement, in living with God, one another, and those outside of God's family. But it can also include reproof, rebuke, and correction. As we see in this letter.
There are many places in Scripture, where wisdom is praised. And part of wisdom is in receiving correction. But there is also wisdom in giving correction.
One part of giving correction wisely is being sure of the facts. That is why Sosthenes is important. He is a witness to the problems of the Corinthian church. He is a trustworthy witness. And someone who is trusted by the Corinthians.
Another part of wise correction is a focus on the positive. The first thing Paul does in this letter is to praise the church for the good in them.
If all we recognize is bad in someone, and hammer away at that, do we communicate any message of hope, and worth, in that person.
The purpose of correction is to communicate wrong areas of thinking, speaking, and acting. But it should also communicate how to do those areas rightly, and why. And it should communicate motivation to change.
None of us are perfect. So, we all need correction. If all we hear about is how wrong we are, we will have no motivation to pursue what is right. Communicating worth, value, and where we excel can have as much effect in enabling us to move in a right direction, as pointing out our wrong direction. It gives hope, and encouragement.
The gospel reminds us, we are all condemned sinners. But the gospel also reminds us that we are loved, and redeemed. It is the second part that moves us to repentance, and pursuit of a new life, a new way of living.