Er, well, actually....
Taute "this" is often used in Koine Greek to refer to a subject appearing in a sentence or paragraph more distantly preceding than the immediate word in front of it, and can also be used in reference to a subject that has been previously described in detail, which means that the "rock" being referred is actually likely to be the great confession of v.16, which Christ had then expounded upon in v. 18. This seems especially likely given the gender disparity between petros and petra, which appears to be a play on words (also very common in scripture).
Well, actually, you need to read post #126.
Great post.
I’ve found He reals something even greater in the observation to Simon Barjona.
Think in terms of the roles of the persons in the Trinity. Discern their identity, and why they are presented to us.
Our Lord and Savior in hypostatic union, is acting in His humanity in this verse. He is trying to communicate a discerning feature between body, sou, and spirit in His observation.
He also manifests His intent to only perform the Will of the Father.
So He notes, He is going to base His Church upon those elected by God the Father. God the Father has the Plan, God the Son executes the Plan, and God the Holy Spirit glorifies the Son and the Plan in its execution.
The hinge is basing everything upon the Plan of the Father as He reveals to us through faith in what He has already established, provided, and maintains.