Matthew 16:18

Thou art Peter; in the Greek, Petros, the same as Cephas-from the Aramaean, or Hebrew of our Lord's day-and meaning, rock.

And upon this rock; in the Greek, petra, that is, rock. The less usual form, Petros, differs from petra in taking the masculine form, because it is given to a man as his epithet. The words "upon this rock I will build my church," have been differently interpreted among Protestants. First, "upon this rock," that is, upon thee, Peter, with allusion to the name "rock," which Christ had given him upon his first interview with him, John 1:42. According to this interpretation, Peter is called a rock only in a lower sense, as an eminent instrument to be employed by Christ in building up his church, just as he is afterwards said to receive the keys of the kingdom of heaven in a lower sense; for in the high sense, Christ alone is the rock on which the church is built, and he alone has the keys of the kingdom of heaven. Isaiah 28:16; 1Pe 2:6; 1 Corinthians 3:11; Ephesians 2:20; Revelation 1:18; Revelation 3:7. Secondly, "upon this rock," that is, upon the confession thou hast just made of me; or rather, upon the great truth contained in that confession, "Thou art the Christ, the Son of the living God". According to either of the above interpretations, Christ alone is the true foundation of the church. As it is written of him, "Behold, I lay in Zion for a foundation a stone, a tried stone, a precious cornerstone, a sure foundation; he that believeth shall not make haste," Isaiah 28:16. The apostle Peter says same, 1 Peter 2:6. Paul also, in Ephesians 2:20, speaks of the church as "built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief cornerstone." Thus, according to the prophet Isaiah and the apostles Peter and Paul, writing under the guidance of the Holy Spirit, the foundation of the church, and of the hopes of all true believers, is, not Peter, or Paul, or any creature, but "Jesus Christ, the same yesterday, today, and forever." Gates of hell; the counsels of the powers of evil. The gates of cities were anciently the places in which deliberations were held and plans formed.