Why is the concept of penal substitution important for Christians?

Penal substitution is a critical doctrine that illustrates how Christ took on the curse of sin by being hung on a tree, fulfilling Deuteronomy 21:23, which states 'cursed is everyone who is hung on a tree'. This doctrine emphasizes that Christ's death was not merely an act of love but also an act of justice, where He bore the punishment due to humanity for sin. By this substitution, God remains just while also providing justification to those who believe. Therefore, understanding penal substitution is vital for grasping the fullness of the gospel message.