Mat 16:19 And I will give to you the keys of the kingdom of heaven: and whatsoever you shall bind on earth shall be bound in heaven: and whatsoever you shall loose on earth shall be loosed in heaven.

This translation is very misleadning. It starts with the term "keys" because Christ lived in a time before keys were in common use. The term Matthew used is more general, meaning any device used for keeping something closed. The terms translated as "bind" and "loose" carry the sense of tying things up rather than locking them up.

In the previous verses in this chapter, Christ has been explaining the relationship between the physical things that we see and the concepts or spirit behind or within them. We can only know the true nature of the physical world if we know their hidden spirit, which we can only learn from God.

Here, Christ is taking that idea one step further. In the context of Peter seeing Christ’s true nature, Christ says that he is giving Peter the ties between the physical, visible, tangible world and the spiritual, hidden, conceptual world. However, Christ goes further here, saying that what we tie up or free on earth will also be locked up or opened up on the conceptual level. This carries the sense to me, that what our limitations in understanding the physical world become our limitations in understanding the conceptual world.

The interpretation of this that says Peter is getting some special power to bind and unbind the laws of heaven (a common interpretation) is a stretch from the original Greek. A less aggressive interpretation would be that Christ is giving Peter an understanding of the connections between the physical world and the spiritual world, seeing that what we see happening on earth results in our ability to see what will happen conceptually or universally.

Here is the Greek:

kai (and) didomi (give) soi (you) kleis (that which holds closed) basileia (kingdom, reign) ouranos (heaven, sky) kai (and) hos (that) ean (if) deo (tied, bound) epi (on) ge (earth) esomai (will be) deo (tied, bound) en (in) ouranos (heaven, sky) kai (and) hos (that) ean (if) luo(unbind, open) epi (on) ge (earth) esomai (will be) luo(unbind, open) en (in) ouranos (heaven, sky)

Alternative translation: and I give you the bindings of the kingdom of heaven and if bound on earth it will be bound in heaven and if freed on earth it will be freed in heaven.

Symbolic version: and I give you the ties of the universal rule and if closed up in the physical level it will be closed up in conceptual level and if opened up on physical level it will be opened up in conceptual level.

"Give" is from didômi, which means "to give," "to grant," "to hand over," and "to describe."

"Keys" is from kleis, which means generally "that which serves for closing." It means " a bar," "a bolt," "a catch," and "a hook." Later, it came to mean "key" because a key follows the same idea.

"You shall bind" is from deô, means "to tie," "to bind," "to fetter," and "to keep in bonds." It is a metaphor for chaining. The term isn't in the second person and itsn't in the future tense. The "you shall" part of this is added by the translator.

"You shall loose" is from luô, which means "to unbind," "to unfasten," and "to open." The term isn't in the second person and itsn't in the future tense. The "you shall" part of this is added by the translator.