16:18 Peter . . . rock. The name “Peter” is a play on the Greek word for “rock” (petra). There are four leading interpretations of this play on words: (a) Peter’s confession that Jesus is “the Christ” (v. 16) is the rock upon which the church is built; (b) Jesus Himself is the rock, as Peter later testifies (1 Pet. 2:5–8); (c) Peter, as the representative apostle, is a foundation in the church (Eph. 2:20); (d) Peter represents by his confession the type of person on which the true church will be built.
The first and second possibilities are often defended by pointing out that Peter’s name is petros and the rock is petra. But this linguistic difference is not significant for this context. The second possibility is unlikely because Jesus describes Himself in this passage as not the foundation but the builder of the church.
If it had not been for the abuse of this passage by the Roman Catholic Church, it is unlikely that any doubt would have arisen that the reference is to Peter. But the foundational rock is Peter as a representative apostle (v. 15 note) whose confession of Christ has been revealed to him by the Father. As Peter himself later declares (1 Pet. 2:4–8), all believers have become “living stones” by virtue of their association with Christ, with the apostles as the foundation (Eph. 2:20, 21; Rev. 21:14). When Peter says that Jesus must not go to the cross, he is not called a foundation rock, but a stumbling block (v. 23 and text note).
gates of hell. In the Old Testament and other literature the “gates of Sheol” or the “gates of death” are equivalent to “death.” “The gates of hell” may also be a reference to “death.”