In his first letter to the Corinthians, the apostle Paul made it clear to them that they must abandon everything that was sinful before the Lord, especially all immorality. Paul said that God judges those who are within the ways, but those who are outside will be separated from us for being wicked.
The church at Corinth was being corrected by Paul to walk uprightly before God, turning away from their evil ways, because they did not belong to the world, and those of the world will be punished by God.
Therefore, the title of this article reflects what God will do with those who are outside:
But them that are without God judgeth. Therefore put away from among yourselves that wicked person.
1 Corinthians 5:13
Many in the town were disordered before God, and so we see the words of the apostle Paul addressing this church through this letter.
Those who are judged by God for their evil behavior will be set apart and punished for their sins, for their wickedness, and because they try to lead astray all those who are right before God.
It is important that you remain firm and have good conduct before the Lord, so that you will not be one of those who will be set apart and cast out for their evil ways.