Which type of thing is why translation is not the work of one day or two, while more definitive of such a text as Mt. 16:19 is by observing how this is manifested in the rest of Scripture. How do we see binding and loosing, and by whom? Was the uniquely a NT phenomenon.
Briefly, we see God allowing the devil to bind Job via physical affliction, and God loosing him - after he prayed for his expert theological "friends" (indicating forgiving them), and likewise "ought not this woman, being a daughter of Abraham, whom Satan hath bound, lo, these eighteen years, be loosed from this bond on the sabbath day?" (Luke 13:16)
And Paul, when the church was gathered together, delivered the incestuous man "unto Satan for the destruction of the flesh," that thru the repentance this work, "the spirit may be saved in the day of the Lord Jesus." (1 Corinthians 5:5)
When this repentance had been accomplished, the congregation as a congregation was enjoined to forgive the man, "Sufficient to such a man is this punishment, which was inflicted of many. So that contrariwise ye ought rather to forgive him, and comfort him, lest perhaps such a one should be swallowed up with overmuch sorrow." (2 Corinthians 2:6,7)
This was not to bring the soul to practical moral perfection so he could enter Heaven or to atone for sin, contrary to the premise of purgatory, but to bring the man to walk in saving faith, which is what appropriates justification, and thus God motivate repentance, contrary to antinomianism.
But when we are judged, we are chastened of the Lord, that we should not be condemned with the world. (1 Corinthians 11:32)
Of course, there is also chastisement of Godly persons in order to further conform them to Christ, like righteous Job, which only occurs in this world with its temptations and trials, and thus it was here that the Lord was made "perfect," in the sense being tempted in all points like as we are, yet without sin. (Heb. 4:15)
Both the binding and loosing was corporately to be done as the sin defiled the body of Christ, and "If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are. (1 Corinthians 3:17) And thus Peter bound the deceivers of the body unto death in Acts 5.
We see a further connection with forgiveness and healing in the case of the man which "was taken with a palsy," whom the Lord, in response to the faith (not the money) of the man's friends, forgave/healed the man, forgiveness meaning the chastisement the man's sins (which could include sins of ignorance) incurred was lifted, and thus forgiveness meant healing.
Whether is easier, to say, Thy sins be forgiven thee; or to say, Rise up and walk? But that ye may know that the Son of man hath power upon earth to forgive sins, (he said unto the sick of the palsy,) I say unto thee, Arise, and take up thy couch, and go into thine house. (Luke 5:23-24)
We also see Paul binding a man with blindness for a season in Acts 13, and Elijah binding the sky that it would not rain for 3.5 years.(1Ki 17:1).
Coming to James 5, he addresses the situation of sickness in the body, and in which case the exhortation "let him call" is to "call for the elders [presbuteros] of the church," thus indicating the sick was an invalid. And it is elders plural that are to be called, with healing thru intercessory prayer being connected to forgiveness as with the palsied man,
And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him. (James 5:15)
Therefore Catholicism is eliminated from this text, as it is presbuteros who are called, and absolutely nowhere is any NT pastor titled "priest" (“hiereus”) apart from the priesthood of all believers, nor is that what presbuteros means (contrary the etymological fallacy that makes presbuteros into a distinctive class of priest based on imposed functional equivalence), nor are NT pastors shown engaging any uniquely sacrificial function such as changing bread into flesh and dispensing it.
In addition, this means of obtaining deliverance is nowhere set forth as a normative practice for all, but is for an invalid and who calls for the elders, plural, and which is to result in healing. But in Catholicism this sppsd sacrament is typically a precursor to death, thus it is contrary to forgiveness and healing going together.
And most likely the sins here were those of ignorance, with forgiveness meaning God will no longer chastise one for something. Following Christ, Stephan "kneeled down, and cried with a loud voice, Lord, lay not this sin to their charge. And when he had said this, he fell asleep." (Acts 7:60)
While the believer who confesses sins with a repentant heart obtains forgiveness, as even David with his capital crimes obtained, yet there are situations wherein a believer is being chastened for sins he carelessly committed and ignored, or was ignorant of. And as God has confected the organic body of Christ (the church) to be much interdependent, so He has regard for intercessory prayer which can obtain deliverance in such cases (as well as for prayer to change hearts to seek forgiveness, etc.).
In addition, this means of obtaining deliverance thru prayer is not limited to the elders, for as James continues,
Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much. (James 5:16)
And for which he invokes the example of Elijah who bound and loosed the heavens, for while being "a man subject to like passions as we are, and he prayed earnestly that it might not rain: and it rained not on the earth by the space of three years and six months. And he prayed again, and the heaven gave rain, and the earth brought forth her fruit." (James 5:17-18)
Thus it is clear that "whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven" (Matthew 16:19) applies to all effectual fervent prayer of righteous believers. Which we need more of and to be so.
ping to post 966 for a discussion of Greek.