received from him the keys of the kingdom of heaven in the person of Peter, that is, the power of binding and loosing sins. For what the church is essentially in Christ, that Peter is symbolically in the Rock—Petra—by which symbolism Christ is understood to be the Rock and Peter the church. Therefore, this church which Peter represented, so long as she prospers among evil men, is by loving and by following Christ freed from evil, but much more does she follow in the case of those who fight for the truth even unto death."
These things Augustine teaches throughout, in agreement with the apostle, that Christ alone is the foundation and Rock upon which the church is built. To this the apostle Peter speaks, when he says: "Unto whom coming, a living stone, rejected indeed of men, but of God elect and precious, ye also, as living stones, are built upon into spiritual houses[1] to be a holy priesthood to offer up spiritual sacrifices unto God through Jesus Christ," I Peter 2:4 sq. For this reason the Scripture continues: "Behold I lay in Zion a chief corner-stone, elect, precious, and he that believeth on Him shall not be put to shame. For you, therefore, that believe is the honor, but for such as disbelieve, the stone which the builders rejected, the same was made the head of the corner and a stone of stumbling and a Rock of offense. For they stumble at the word and do not believe that whereunto they were appointed." Paul also said: "Israel following[2] after a law of righteousness did not arrive at the law of righteousness. Wherefore? Because they sought it not by faith but[3] by works. They stumbled at the stone of stumbling, as is written, Behold I lay in Zion a stone of stumbling and a rock of offense, and he that believeth on him shall not be put to shame," Romans 9:31 sqq. Behold how these two Roman apostles and bishops, Peter and Paul, prove from Scripture that the Lord Jesus Christ is
