What does 1 Corinthians 5:8 mean?

Paul has commanded the Christians in Corinth to gather as the church and to remove from among them a man who was known to be in an ongoing sexual relationship with his father's wife (1 Corinthians 5:1–5). To drive home how important this is, Paul has used a metaphor of leavened bread during the Jewish Passover celebration. Jewish people were to remove any trace of leaven from their homes and eat only unleavened bread during the Passover.

In the previous verse, Paul wrote that the Christians in Corinth were already unleavened or purified. This is because Christ, the Passover lamb, had already died to pay the price for all their sin. Now the time had come for the Corinthians to live up to what they already were. They must remove the sin from among them that Christ had died for.

Paul calls them to celebrate the festival. He does not seem to mean that they should observe the Passover celebration. Instead, he seems to be saying that they should always be in a spirit of celebrating the truth that Christ's blood had paid for their sin. For Christians, this in an ongoing reason to rejoice, not a once-a-year celebration. Some Bible teachers connect Paul's mention of the festival with the Christian practice of communion.

In either case, Paul writes that those who are celebrating the forgiveness of their sins by the blood of Jesus must not do so while living in sin, the leaven of "malice and evil." Such sin has no place among those who rejoice over being forgiven for their sin. Instead, such rejoicers should live with sincerity and truth.