Specifically, Matthew 16:18-19.  I've quoted it from KJV below.  I said read 16-19 for better context.

These verses have nothing to do with forgiving sins or a church, and everything to do with Peter recognizing Jesus was the Messiah and that the "kingdom of heaven is at hand" (Matthew 3:2).

The word ekklesia (translated here in verse 18 as Church), merely means 'assembly'. "Kingdom of heaven" is a phrase only used in Matthew and it refers to the Genesis 13 promise of assembling Jews into a literal kingdom on earth in Israel with Jesus as the King ruling from Jerusalem.

There are many churches out there with doctrines based in replacement theology - the practice of taking the promises made to Israel and spinning them so they apply to the 'church' (so you better do what they say!). It made sense for a long time... not so much after 1948.

Genesis 13:14-17
And the LORD said unto Abram, after that Lot was separated from him, Lift up now thine eyes, and look from the place where thou art northward, and southward, and eastward, and westward: For all the land which thou seest, to thee will I give it, and to thy seed for ever. And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth, then shall thy seed also be numbered. Arise, walk through the land in the length of it and in the breadth of it; for I will give it unto thee.

Thanks for the reply.  What does the binding and loosing verse mean to you?

If I recall correctly, Catholicism is amillenial, meaning it rejects the belief that Jesus will have a literal, physical reign on the earth for 1000 years (Revelation 20). If you adhere to that belief as well, then my explanation will probably be meaningless.

This earthly kingdom, even with Jesus as king, will have an administration to carry out day to day duties. The 'keys' mentioned in Matthew 16:19 represent authority in this kingdom. In Matthew 18 the disciples ask Jesus "who would be greatest in the kingdom of heaven?" and he promptly gives them a quick lesson about humility. Binding and loosing are mentioned again in this chapter with a little more detail.

Parts of Matthew 18 state that sin will still be present during this kingdom period, and it will be the job of this administration to settle disputes. In verses 15-17 it details the steps on how to deal with an accused offender with increasing levels of severity. In this context, binding and loosing are judicial decisions on earth, declaring either guilt (bound) or innocence (loose) before the LORD who will oversee the proceedings to the extent that even false witnesses will be exposed and judged.

Matthew 18:15-20
Moreover if your brother sins against you, go and tell him his fault between you and him alone. If he hears you, you have gained your brother. But if he will not hear, take with you one or two more, that by the mouth of two or three witnesses every word may be established. And if he refuses to hear them, tell it to the church. But if he refuses even to hear the church, let him be to you like a heathen and a tax collector. Assuredly, I say to you, whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven. Again I say to you that if two of you agree on earth concerning anything that they ask, it will be done for them by My Father in heaven. For where two or three are gathered together in My name, I am there in the midst of them.

Deuteronomy 19:15-19
One witness shall not rise against a man concerning any iniquity or any sin that he commits; by the mouth of two or three witnesses the matter shall be established. If a false witness rises against any man to testify against him of wrongdoing, then both men in the controversy shall stand before the LORD, before the priests and the judges who serve in those days. And the judges shall make careful inquiry, and indeed, if the witness is a false witness, who has testified falsely against his brother, then you shall do to him as he thought to have done to his brother; so you shall put away the evil from among you.

I'm sorry, that's sad

Where in the Bible, do you find the word Bible. You don't. Luther added it.

Though we can never be sure if we are "saved" or even if we are in a state if grace, until judgement, we for sure know that Pope Francis, and the like are on the road to perdition, and that Catholics need to hold fast to Sacred Scripture and Sacred Tradition.

You don't have to be a priest* to forgive sins, but you need to for God to forgive you.

Matthew 6:9-13
9 Pray then like this: “Our Father in heaven, hallowed be your name.
10 Your kingdom come, your will be done,  on earth as it is in heaven.
11 Give us this day our daily bread,
12 and forgive us our debts, as we also have forgiven our debtors.
13 And lead us not into temptation, but deliver us from evil.

*You are actually a priest (1 Peter 2:9)

Been here for 16 years and just had my first doubletap.

What is the Church as you understand it?

You are correct in that Catholic Church does not teach millennialism.  That is about the extent of what I know of that subject.  The following is simply an uneducated opinion, so feel free to ignore it altogether.

That interpretation of the Matthew 18 seems like a far stretch for the following reasons:

1) It seems to contradict the traditional context of forgiveness of sins by priests, a practice held by the majority of Christendom for two millennia.
2) Christ is King now.  Why should that verse not apply until the putative "thousand years reign?"
3) It doesn't seem to make sense that the rest of Matthew 18, or the entire Gospel of Matthew for that matter, was meant as advice for the age of the apostles, while the part in question would not apply until thousands of years later.

I believe in one, holy, catholic, and apostolic Church.  I think this article does a nice job in peeling a layer.

As of last year, the Catholic Education Resource Center sated that there are appropriately 1 billion Catholics and 1 billion Protestants. Therefore, the majority of Christians don't believe in that practice.
Since the Protestants broke apart from the Catholics in early 1500's, your statement of 2 millennia is also incorrect.
Almost none of the Protestants believe in priests having the authority to forgive. As Jesus Christ himself said, pray Our Father .... forgive us our sins......
He never said to pray to Mary. He never taught that she was an intermediary. He never taught to pray to any man. He never taught to ask any man to forgive us our sins; only to ask forgiveness if we committed an offense against that person.
He also taught that it is imperative that Christians forgive others or that God, the Father will not forgive us. The Catholic religion does not teach that.
Jesus also told parables explaining, and literally said, that there is one life, then the judgement; no purgatory, no second chance for relatives to pay the priest to move you from your undecided fate to heaven.

It is not putative, it is clearly stated as fact more than one time in the New Testament. Jesus Christ is King now. It is clearly stated in the New Testament. His Kingdom will come after the tribulation.
Satan will be bound for that 1000 year reign. At the end, Satan will be released and he will be permitted to again deceive people for a short time. There will be people that will rebel against Christ at the end of His 1000 year reign, just as 1/3 of the angels rebelled against God prior to creation of man.
After the rebellion after Christ's 1000 year reign we will have the great day of judgement and Satan will be bound and thrown into the bottomless pit, all the unsaved will be cast into the lake of fire, hell/ hades will also be cast into the lake of fire, then the old earth and heaven will be destroyed and a new earth and heaven will be created.

Good point on your correction to 1).  I should have been more clear.  What I meant to convey is that of the total number of Christians, who lived at any point in time during the past 2,000 years, most believed in the forgiveness of sins in the context of this thread.  That is not a Roman Catholic thing only.  There are even protestants who believe in it.  I'm not addressing your other points because (a) they are out of scope for this conversation and (b) we've discussed them ad nauseam here before.  If you are genuinely interested in those other topics, I recommend you start new threads.

On 2), you are addressing of my choice of language instead of the actual point.  I was not arguing for or against millennialism.

Yep, that's odd to me.

Edit: referring to the material in the link you sourced.

Yes, Christ is King of kings, but His first coming was to present Himself to Israel as King of the Jews, fulfilling promises made to Abraham and his seed. That interpretation of Matthew 18 holds water just by reading more of Matthew.

Matthew 2:1-2,6
Now when Jesus was born in Bethlehem of Judaea in the days of Herod the king, behold, there came wise men from the east to Jerusalem Saying, Where is he that is born King of the Jews? for we have seen his star in the east, and are come to worship him. And thou Bethlehem, in the land of Juda, art not the least among the princes of Juda: for out of thee shall come a Governor, that shall rule my people Israel.

Matthew 4:17
From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.

Matthew 4:23
And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom.

Matthew 10:5-7
These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not But go rather to the lost sheep of the house of Israel. And as ye go, preach, saying, The kingdom of heaven is at hand.

This kingdom was 'at hand'... within reach. The gentiles aren't part of this. Had Israel not rejected Jesus, the "thousand year reign" would have started roughly 2000 years ago. Not until Paul was the mystery of the church revealed: that God would take salvation to jew and gentile alike, justified / forgiven by grace through faith in the finished atonement at the cross.

Romans 3:24-26
Being justified freely by his grace through the redemption that is in Christ Jesus: Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God; To declare, I say, at this time his righteousness: that he might be just, and the justifier of him which believeth in Jesus.

Galatians 3:8
And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed.

Galatians 3:21
Is the law then against the promises of God? God forbid: for if there had been a law given which could have given life, verily righteousness should have been by the law. But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe.

1 Corinthians 15:1-4
Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures:

Logical but a bold statement.

Best I recall from the last book of the Bible, there's not going to be any new revelations.

To be clear, I wasn't advocating it.

I didn't think you were. Just the point that it IS a logical starting place for much of Protestantism, and far more honest than the "hidden original church" idea posited by some.

Would you mind clarifying what you mean by that?

I think he's saying that some protestants claim their denomination either restores the church to it's original legitimacy or existed in perfect form in some hidden tradition.

For the first claim, I know I have my own personal issues with the RCC but it seems very odd to me that a church founded by Christ somehow completely failed in everything but it's preservation of a particular Biblical canon.  But where did "sola scriptura" come from exactly?  It's not in said Bible (it'd be circular logic anyway if it was).  I'm not aware of a reference to it prior to the 1500s.

With respect to the second claim, I've heard some Baptists claim their tradition descends from the original church that somehow sidestepped the RCC for almost a couple thousand years.  I've seen posters suggesting exactly that.  Maybe it did, but it's never clear to me as to how this could have happened.  It certainly didn't come from Lutheranism/Anglicanism/Calvinism, as these all came from the RCC.  So where were the baptists who were carrying the torch, say around 1000AD?

Oh my, how did I miss this?

FWIW, the Orthodox churches that split from Rome long before the word Protestant was a thing (or that Rome split from, depending on your POV) see confession the same way, and are general much more “old school” about it than the Catholic Church.

Here’s a small taste.

https://pomog.org/church-rules-for-confession-and-holy-communion-en/

And, if there were secret communities of Baptist’s with a set of accepted doctrines around since the time of Christ, how come they all ended up in the English speaking world and haven’t surfaced elsewhere, such as in the East?

The RC Church had similar rules Pre 60's Vat. II.

6. Ask forgiveness and reconcile yourself with everyone with whom you have had an argument, misunderstanding or any deterioration in relationship. By taking Communion without full reconciliation with everyone we do ourselves great harm.

Preferably sometime before Mass and with those we actually have a falling out with. Now we get to sport a fake smile, exchange germs, make hippy peace signs, and small talk with the strangers around us during the part of Mass when we should be in deep contemplation of receiving the Holy Eucharist.

First, as the institution who complied the Bible, the nothing in Catholic doctrine or practice is contradicted by the Bible.

Protestant churches specifically have the duty to show that Luther, Calvin or Zwingil have more current or complete revelation of God's word than the early Fathers. Its a really tall order, because if you believe in the Bible, then read the Catecism, you see where Catholic Doctrine and practice, to include some tradition, dates to the earliest Church. Now, there was some changes along the way (for example the increase in private Confession, versus public Confession, especially for specific sins) but both of these practices stretch back to the earliest parts of our Church.

A logical starting point for Protestantism is a certain level of Gnosticism. Right or wrong, it would have logical consistency as I understand Gnostic thought

Oh, no doubt, and there is good reason I use the term “old school.”

I find Eastern Orthodox theology and practices worth pointing out in some of these threads for various key reasons.

1) They are easy to find on the ’net as current discussion related to modern practices.

2) They are clearly separate from “Roman” influence, and thus provide some insulation from the usual Jack Chick style conspiracy theories, while showing how certain beliefs date back to the beginnings of Christianity.

3) For those who still want to espouse the conspiracy theories, they have to contend with explaining how the Bishop of Rome must simultaneously never have really been “first among equals” and in any unique leadership role from the earliest days of the Church, while also explaining how non-Christian or pagan theology not only infiltrated the Christian Church in Rome, but also managed to do the same to the other Churches of the New Testament (unless they accept such practices were widely understood from the earliest days).

If a Baptist (insert any Prot denomination) minister was asked to pray for healing over a sick person, and that person indeed was healed, would the 'power of healing' be attributed to God or to the preacher?

Likewise the Catholic priest grants absolution. The forgiveness of sins that accompanies absolution comes from God.