1 Corinthians 5
v1-6: "The detestable sins of professing Christians are noted quickly and reported widely." Those outside the church are watching us and will speak up if we sin a scandalous way. Church discipline is vital for the spiritual good of the unrepentant church member by helping them to see and acknowledge their own errors, and for the maintenance of the purity of the church by not turning a blind eye to the guilt and shame of those within.
v7-8: "Christian churches should be pure and holy, and not keep such corrupt and scandalous members." Each individual member must be holy by cleansing "themselves of all impurity of heart and life" and avoiding "the sins to which they themselves were once most devoted and the prevalent evils of the places where they live and the people among whom they live."
v9-13: "The dread of sin wears off, however, by frequent association with corrupt Christians."