[Havoc]

You're right. And I don't see anyone contesting that, so I'm not sure of the point you think you're making. petros and petra are two states of being that are inequalities. Cephas or Kephas does directly translate to petros - not to Petra. Thus the difference in the words. Thus the difference in the sentence structure which you'll note properly modifies the greek gender of the two words, etc.

[Claud]

Cephas or Kephas does directly translate to petros - not to Petra.

I'm curious as to what's your evidence for saying that? I'm not a Semiticist, but from what I've heard the semantic range of Aramaic Kephas would include any and all of those putative variations.

My point is as follows. To say that Christ was making some kind of theological point between petros "pebble of Peter"/petra "rock of faith" loses all of its force when Christ actually named him "Kephas". Far more consonant with John 1:42 is that the gender of petra was simply revised to reflect the gender of Peter when his name was translated to Greek. And really the whole rest of the passage describes a grant of authority to a single person being addressed: "soi".