There are more kinds of leavening that can creep into your house than that of the Pharisees. Sexual immorality, greed, idolatry, mockery, drunkenness, etc. Like the chametz (leavened bread) that must be destroyed before #passover, true repentance requires a deliberate separation from sin in your life. We have to guard against these in our congregations too.
1 Corinthians 5:7,11