Final answer:
Sanctifying grace is necessary in Christianity to cleanse a person of original sin and restore them to a state of holiness. It is imparted through the sacraments of baptism, communion, and confession, and is needed for salvation and entrance into heaven.
Step-by-step explanation:
Sanctifying grace is understood as needed in Christianity because it is believed to cleanse a person of original sin and restore them to a state of holiness. This grace is imparted through the sacraments of baptism, communion, and confession. It is needed to gain salvation and entrance into heaven.
According to medieval Christian beliefs, without the purification of original sin through baptism, even a newborn who died would be denied entrance to heaven. Communion connected believers spiritually with God and the belief in transubstantiation emphasized the transformative power of this sacrament. Confession was necessary for the forgiveness of sins, acknowledging the constant human tendency to commit wrongdoing.