The concept of priesthood in the Bible has evolved from the Old Testament to the New Testament, and its role today is understood through the lens of these scriptural developments. In the Old Testament, the priesthood was established through the line of Aaron, with the Levites serving as assistants. The primary duties of the priests included offering sacrifices, maintaining the temple, and acting as mediators between God and the people (Exodus 28:1, Leviticus 9:7).

In the New Testament, the role of the priesthood undergoes a significant transformation with the coming of Jesus Christ, who is described as the ultimate High Priest. Hebrews 4:14-16 states, "Therefore, since we have a great high priest who has passed through the heavens, Jesus the Son of God, let us hold firmly to what we profess. For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who was tempted in every way that we are, yet was without sin. Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need."

The New Testament introduces the concept of the "priesthood of all believers," as articulated in 1 Peter 2:9 : "But you are a chosen people, a royal priesthood, a holy nation, a people for God’s own possession, to proclaim the virtues of Him who called you out of darkness into His marvelous light." This passage emphasizes that all believers have direct access to God through Christ and are called to serve as priests in their own right, offering spiritual sacrifices and proclaiming the Gospel.

In contemporary Christian practice, the role of the priesthood is often seen in two primary forms: the ordained ministry and the universal priesthood of believers. The ordained ministry, which includes pastors, priests, and other church leaders, is tasked with shepherding the congregation, administering the sacraments, preaching the Word, and providing spiritual guidance. Ephesians 4:11-12 highlights this role: "And it was He who gave some to be apostles, some to be prophets, some to be evangelists, and some to be pastors and teachers, to equip the saints for works of ministry and to build up the body of Christ."

The universal priesthood of believers, on the other hand, emphasizes the responsibility of every Christian to live a life of holiness, engage in personal and communal worship, and participate in the mission of the Church. This includes intercessory prayer, acts of service, and sharing the Gospel with others. Romans 12:1 encourages believers in this regard: "Therefore I urge you, brothers, on account of God’s mercy, to offer your bodies as living sacrifices, holy and pleasing to God, which is your spiritual service of worship."

In summary, the role of the priesthood today is multifaceted, encompassing both the ordained ministry and the active participation of all believers in the life and mission of the Church. Through these roles, the priesthood continues to serve as a vital conduit for God's grace and truth in the world.