Sermon of Blessed Augustine, Bishop of Hippo (Ipponesia)
On this present day Holy Church piously remembers the suffering of the Holy Glorious and All-Praiseworthy Apostles Peter and Paul. Saint Peter, the fervent follower of Jesus Christ, for the profound confession of His Divinity: "Thou art the Christ, the Son of the Living God", – was deemed worthy by the Saviour to hear in answer: "Blessed art thou, Simon... I tell thee, that thou art Peter (Petrus), and on this stone (petra) I build My Church" (Mt. 16: 16-18). On "this stone" (petra), is on that which thou sayest: "Thou art the Christ, the Son of the Living God", – it is on this thy confession I build My Church. Wherefore the "thou art Peter": it is from the "stone" (petra) that Peter (Petrus) is, and not from Peter (Petrus) that the "stone" (petra) is – just as how the christian is from Christ, and not Christ from the christian. Do you want to know, from what sort of "rock" (petra) the Apostle Peter (Petrus) was named? – Hear ye the Apostle Paul: "I do not want ye not to know, brethren, – says the Apostle of Christ, – how our fathers were all under a cloud, and all passed through the sea: and all in Moses were baptised in the cloud and in the sea. And all thus eating spiritual food, and all thus drinking spiritual drink: for they did drink from the spiritual accompanying rock: for the rock indeed was Christ" (1 Cor. 10: 1-4). Here is the from whence the "Rock" is Peter.