These days, the phrase "vicar of Christ" used almost exclusively within the Catholic Church. Among Catholics, it is applied almost exclusively to the clergy. Among the clergy, it is applied almost exclusively to the Pope.
This telescoping interpretation certainly has an impressive pedigree. As a papal honorific, it dates to the synod of 495 during the regnal years of Pope Gelasius I. As a general descriptor of the clergy (specifically the bishops), it dates back to the writings of St. Ignatius of Antioch, a student of St. John the Apostle and the third bishop of Antioch, reportedly appointed by St. Peter himself. The doctrine can be found in both the Catechism and Lumen Gentium, the Dogmatic Constitution of the Church.
But while this gloss of the phrase is certainly accurate, I find it rather inadequate.
The word "vicar" is derived from the Latin vicarius, meaning 'deputy' or 'representative.' We derive "vicarious" from the same root. A vicar stands and speaks on behalf of someone else.
But is this not the Church? After His resurrection and ascension, Christ left His ongoing work of spreading the gospel to the twelve apostles. The twelve, and all who learned the gospel by their testimony, were commissioned (Matthew 28:18-20, Acts 1:8) as members of His Body and witnesses to His Gospel to baptize in His Name.
This is widely held as the meaning of 1 Peter 2:4-5, which reads: "And coming to him as to a living stone which has been rejected by men, but is choice and precious in the sight of God, you also, as living stones, are being built up as a spiritual house for a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ." In a similar vein, after quoting Isaiah 28:16, Psalm 118:22, and Isaiah 8:14, the passage continues in verses 9-10 with a litany of Old Testament references: "But you are 'a chosen race' [cf. Isaiah 43:20], a 'royal priesthood' [cf. Psalms 110:4 and Isaiah 61:6], a 'holy nation' and 'a people for God's own possession' [cf. Exodus 19:5-6], so that you may proclaim the excellencies of Him who has called you out of darkness into His marvellous light."
Certainly, this principle can be found through the Christian message. Adam sinned as a representative of humanity. The high priest stood vicariously for the people of Israel to offer the annual sacrifice within the Holy of Holies. Christ came as a 'second Adam' to redeem humanity by His vicarious sacrifice. The apostles were first deputized by Christ to act as His representatives during His public ministry, then commissioned and empowered by the Holy Spirit to serve as "ministers of Christ and stewards of the mysteries of God" (1 Corinthians 4:1). We participate vicariously in Christ's holiness as "sons of God" (Galatians 2), confess our sins vicariously to God through one another (James 5:16), and intercede on each others' behalf through prayer (1 Timothy 2:1).
The principle of vicariousness is at the heart of authentically Catholic teaching. Indeed, the foundational Catholic doctrine of sacramentality (the understanding that God dispenses grace through vessels of the physical world) is itself an expression of this very principle. Creation is the vicar of her Creator.
One final point: I find it interesting that the same phrase "vicar of Christ" was applied in the early Church not only to the bishops but also to the Holy Spirit itself, at least in the writings of Tertullian. For indeed the Holy Spirit is central and instrumental to the Great Commission and the Church's ongoing work. It enables the apostles to preach with boldness at Pentecost, and even today it enables us to confess that "Jesus is Lord" (1 Corinthians 12:3).
In our individual bodies, we are called "temples of the Holy Spirit" (1 Corinthians 6:19). The corporate body of the Church may be considered a temple in the same way.
Just as Christ is the Body of the Church, the Holy Spirit is indeed her soul.
The Church is empowered and ensouled by the Holy Spirit. This is the root of Catholic teachings about Scripture and Tradition, at the heart of the Sacred Magisterium itself. But I leave that subject for the next series of posts.