Matt 16:19, wherein Jesus addresses Peter, reads as follows:
And I will give unto thee the keys of the kingdom of heaven; and whatsoever thou shalt bind on earth shall be bound in heaven; and whatsoever thou shalt loose on earth shall be loosed in heaven.
With respect to the language of "binding" and "loosing," it is generally agreed by commentators that the Greek (ὃ ἐὰν δήσῃς ἐπὶ τῆς γῆς ἔσται δεδεμένον ἐν τοῖς οὐρανοῖς, καὶ ὃ ἐὰν λύσῃς ἐπὶ τῆς γῆς ἔσται λελυμένον ἐν τοῖς οὐρανοῖς) is using periphrastic constructions and that a better translation would be:
Whatever you bind on earth will have already been bound in heaven, and whatever you loose on earth will have been already loosed in heaven.
In other words, the binding and loosing is a recognition of something already ratified by God; it is not a theological case of the tail wagging the dog, so to speak.
Interestingly, the Book of Mormon seems to capture this nuance to the binding and loosing power of the keys in Helaman 10:5-10:
And now, because thou hast done this with such unwearyingness, behold, I will bless thee forever; and I will make thee mighty in word and in deed, in faith and in works; yea, even that all things shall be done unto thee according to thy word, for thou shalt not ask that which is contrary to my will. Behold, thou art Nephi, and I am God. Behold, I declare it unto thee in the presence of mine angels, that ye shall have power over this people, and shall smite the earth with famine, and with pestilence, and destruction, according to the wickedness of this people. Behold, I give unto you power, that whatsoever ye shall seal on earth shall be sealed in heaven; and whatsoever ye shall loose on earth shall be loosed in heaven; and thus shall ye have power among this people. And thus, if ye shall say unto this temple it shall be rent in twain, it shall be done. And if ye shall say unto this mountain, Be thou cast down and become smooth, it shall be done. And behold, if ye shall say that God shall smite this people, it shall come to pass.
Notice that there is a one-to-one correspondence between Nephi’s binding and loosing and the will of God. As with Matt 16:19 (cf. Matt 18:18), theologically speaking, the dog is wagging the tail, not vice-versa.
