Why is inward purity important for Christians?

Inward purity is profoundly important as it represents the core of a believer's relationship with God. According to Jesus' teachings in Luke 11, the Pharisees prioritized ceremonial rituals while their hearts were tainted with wickedness. This shows that external behaviors alone do not justify anyone before God. True Christian faith must stem from a heart that has been transformed by the grace of God through Christ, leading to a life that seeks to reflect God's character in both thoughts and actions.