Final answer:
The common priesthood of the faithful is the term that describes the spiritual participation of all baptized individuals in Christ's priesthood, allowing them to partake in His work of salvation.
Step-by-step explanation:
The common priesthood of the faithful refers to the priesthood shared by all who are baptized, signifying a participation in the spiritual priesthood of Christ and His work for salvation. This concept is rooted in the Christian belief that through baptism, all Christians are consecrated and joined to Christ's priesthood, capable of participating in certain ministerial functions. This idea opposes the notion that only the ordained clergy could perform sacred rites and minister sacraments, which was a central feature of the medieval Church's understanding of spiritual authority. According to the teachings presented, all baptized individuals have the potential to baptize, preach, and perform other sacred duties, especially in cases of necessity or absence of ordained clergy.