Penal substitution is a Christian doctrine that teaches that Jesus Christ took upon himself the punishment for sin that we deserve, thereby satisfying God's righteous wrath against our sins. This concept is based on the belief that humanity has fallen short of God's standards and deserves to be punished for their wrongdoings. According to this doctrine, Jesus willingly took upon himself the penalty for sin by being crucified, thereby taking the place of those who believe in him and receiving the wrath of God that they deserve. This act of substitution is seen as a form of atonement or reconciliation between humanity and God, allowing believers to be forgiven and restored into right relationship with their Creator.