Pastors pride 2

I gather that the issue is the temporal sense of the periphrastic ἔσται δεδεμένον/λελυμένον from Matthew 16:19. I was taught that the voice of the participle determines the voice of the periphrastic construct. Here, δεδεμένον/λελυμένον is in the middle voice, suggesting that the thing being bound/loosed plays a part in its own binding/loosing. The perfect tenseform of the participle has a stative aspect and brings the participle (verb) into the foreground. Porter's "Fundamentals of New Testament Greek" (chapter 28) lists the future equative + perfect participle as equivalent to the future perfect indicative of the participle's finite verb, here "will have been bound/loosed". The temporal sense of the periphrastic construct is future. Putting these together suggests that the binding/loosing on earth plays a part in the equivalent binding/loosing in heaven, with the 'foreground' emphasis on the thing that happens in heaven and 'background' context of the thing that happens on earth. It's not that the binding/loosing in heaven is already a done deal from eternity past to eternity future, but that the state of the thing bound/loosed in heaven is correlated to the binding/loosing on earth: what will in future be done in heaven in this case reflects what is being done now on earth. In your young pastor's translation, it sounds like the binding/loosing in heaven is something encompassing all time from eternity past to eternity future and is independent of the binding/loosing on earth. That is, the binding/loosing on earth just happens to always correspond to the eternal heavenly state of the thing that was bound/loosed. This make the metaphor of the key a lot less meaningful. However, if we take the view that the earthly binding/loosing gets reflected in a future heavenly binding/loosing, holding the key becomes a weighty matter. Peter's opening of the kingdom to Cornelius (and by extension to all Gentiles) in Acts 10 can then be considered a fulfilment of this, where the Peter's earthly loosing of forgiveness to "everyone who believes in him" is swiftly followed by the Holy Spirit's loosing or pouring out "even on Gentiles". Although your young pastor could argue that election was done before creation (Eph 1:4), the sense in Acts 10 is that Peter's earthly pronouncement was somehow key to the spiritual blessing.