Augustine’s logic is that the rock is Christ, and since Peter confesses Christ, Peter is the rock in confessing Christ. Thus, Peter is the rock not as the first holder of an ecclesiastical office, but as representing the apostolic confession of Christ. This interpretation is supported by the fact that all throughout the New Testament, Christ is called the rock on which the church is built (Eph. 2:20; 1 Cor. 10:4; 1 Peter 2:8; drawing from Ps. 118), with the apostles as a group also at times participating in this imagery as well (Eph. 2:20; Gal. 2:9).
As you come to him, the living stone, you become living stones built into a spiritual house (1 peter2)
