Q: When the Greek version of Matthew’s Gospel translates Jesus’ Aramaic statement to Peter, “You are kepha (rock) and on this kepha (rock) I will build my church” (Matt. 16:18), why does it use petros to translate the first instance and petra the second? Why doesn’t it just use petros twice and say, “You are petros and upon this petros, I will build my church”?

A: There are three possibilities:

1) It is simply an accident of translation from the Aramaic which Jesus spoke, and there is no further explanation.

2) It is a stylistic variation to avoid a redundancy in terms. For example, if I was speaking to a Mr. Stone, it would sound clunky and redundant to say, “I tell you truly, you are Stone, and on this Stone I will build my organization.” It would sound better (less redundant) to say, “I tell you truly, you are Mr. Stone, and on this Rock I will build my organization.” We regularly use such stylistic variation in English to avoid redundant language (that is the whole reason for pronouns – I, me, my, he, him, his, she, her, hers — to avoid endlessly repeating the same nouns over and over again), and stylistic variation is used in other languages as well, Greek included. It makes things sound better and smoother.

3) Even if there were, as Fundamentalists often claim, a difference between the meanings of petros and petra, one meaning “small stone” and the other “large rock” (and all the linguistic evidence is against there being this distinction in first century Greek, as even Protestant scholars like D. A. Carson admit; see his commentary on Matthew in the Expositor’s Bible Commentary, published by Zondervan Press) then the second would simply be an intensifier of the first. Thus Jesus’ statement would be read synthetically (rather than antithetically) to mean, “You may appear to be a small stone, Peter, but on the large rock which you really are, I will build my Church.”

Personally, in view of the linguistic evidence showing that petros and petra were synonyms in first century Greek, I incline toward the second view, but all three are possible.