I just want to add this,
Matt16:17 only has one and only one topic, and it has nothing to do with any kind of rock or any kind of confession,
Its whole subject is and in every loving heart be, the new church now and forever deals with man one on one, God deals with man and man with God with NO MIDDLE MAN (priest) The "SUBJECT MATTER" IS
REVELATION He Reveals to Men now... 
Please try to forget all the tricks the mother church has use for 2009 years to get us off the True Subject Matter of this verse. or forget the rock and confession lies. Yes those meanings are there, but how often have you been taught of "old testament" is through the high priest in the temple, "new testament" is God's Anointed the high priest in the new temple of one body that he bought with His blood.
Don't forget the SUBJECT MATTER OF THIS
iT IS REVELATION TO HUMANS ONE ON ONE (MAN AND GOD)
Lee