The Corinthians had a serious case of sexual immorality going on in their local assembly.  Rather than mourning over the sin and disciplining the offender, they were "puffed up." Paul instructs them to hand the man over to Satan for the destruction of his flesh. The end goal, however, is the salvation of the man's spirit. Paul's hope is that this would drive the man to repentance and restoration.  Paul then reminds them of who they are in Christ. Just as they had been redeemed by the Passover Lamb (Jesus Christ) they are to get out the old "leaven." Finally, he exhorts them not to fellowship with professing believers who sin rebelliously.