This translates the Greek word peʹtra (feminine gender), which designates a mass of rock (Mt 7:24, 25; 27:51, 60; Lu 6:48; 8:6, 13; Re 6:15, 16) and therefore differs from peʹtros (masculine gender and employed as a proper name, Peter), meaning “piece of rock.” This distinction makes it clear that, when saying to Peter, “You are Peter, and on this rock-mass I will build my congregation,” Jesus was not using synonymous terms. (Mt 16:18) Even in the Aramaic (Syriac) version the distinction is apparent from a difference in the gender of the particle preceding the word kiʼphaʼ, used for both “Peter” and “rock.” The masculine verbal pronoun (hu) precedes “Peter,” but “rock” is preceded by the feminine demonstrative adjective (hadeʼ).

That the apostles did not understand Jesus’ statement to signify that Peter was the rock-mass is evident from the fact that they later disputed about who seemed to be the greatest among them. (Mr 9:33-35; Lu 22:24-26) There would have been no basis for such disputing had Peter been given the primacy as the rock-mass on which the congregation was to be built. The Scriptures clearly show that as foundation stones, all the apostles are equal. All of them, including Peter, rest upon Christ Jesus as the foundation cornerstone. (Eph 2:19-22; Re 21:2, 9-14) Peter himself identified the rock-mass (peʹtra) on which the congregation is built as being Christ Jesus. (1Pe 2:4-8) Similarly, the apostle Paul wrote: “For they [the Israelites] used to drink from the spiritual rock-mass that followed them, and that rock-mass meant the Christ.” (1Co 10:4) On at least two occasions and in two different locations the Israelites received a miraculous provision of water from a rock-mass. (Ex 17:5-7; Nu 20:1-11) Therefore, the rock-mass as a source of water, in effect, followed them. The rock-mass itself was evidently a pictorial, or symbolic, type of Christ Jesus, who said to the Jews: “If anyone is thirsty, let him come to me and drink.”​—Joh 7:37.

It is also of interest that Augustine (354-430 C.E.), usually referred to as “Saint Augustine,”  at one time believed that Peter was the rock-mass but later changed his view. Lange’s Commentary on the Holy Scriptures (Mt 16:18, ftn, p. 296) quotes Augustine as saying: “The rock is not so named from Peter, but Peter from the rock (non enim a Petro petra, sed Petrus a petra), even as Christ is not so called after the Christian, but the Christian after Christ. For the reason why the Lord says, ‘On this rock I will build my church,’ is that Peter had said: ‘Thou art the Christ, the Son of the living God.’ On this rock, which thou hast confessed, says he, I will build my church. For Christ was the rock (petra enim erat Christus), upon which also Peter himself was built; for other foundation can no man lay, than that is laid, which is Jesus Christ.”​—Translated and edited by P. Schaff, 1976.