Jesus would have spoken in Aramaic, correct? I don't know either Greek or Aramaic (some would say I struggle mightily with English), but I suppose we would have to go back to Aramaic to do a proper analysis?
Well, actually not. Scripture wasn’t written in Aramaic.
But you raise a good point. Aramaic is important to understand Matthew 16:18. The Catholic haters will say that the Rock on which Christ builds his Church is not Peter. They look to the Greek and see petra and petros, and say this proves that Peter is not the rock. They don’t understand gender in the Greek language. In Greek, Christ would not have called Peter ‘petra’ because petra is a feminine noun, so it is changes to petros, a male noun since it is referring to a man. It is the same meaning, but only the gender of the noun is different.
But what about the Aramaic? Rock in Aramaic is Kepha. And what does Kepha mean? It means a rock, the same as petra. What Jesus probably said to Simon in Matthew 16:18, in Aramaic, was this: ‘You are Kepha, and on this Kepha I will build my Church.’ Totally consistent with Peter as the Rock.