What do we do with false prophets?

When I started studying the Bible in high school, I remember feeling like I understood the concept of the false prophet pretty well. God says in Deuteronomy 18:20-22, "But the prophet who presumes to speak a word in my name that I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die. [Some translations say, "must die."] And if you say in your heart, ‘How may we know the word that the Lord has not spoken?’— when a prophet speaks in the name of the Lord, if the word does not come to pass or come true, that is a word that the Lord has not spoken; the prophet has spoken it presumptuously. You need not be afraid of him."

Now, I certainly didn't think that we were still supposed to put false prophets to death in our modern times. But I was under the impression that, if someone were to either A) say that God gave him a prophecy and then that prophecy didn't come to pass, or B) make a prophecy that did come to pass in the name of someone other than God, then we should ignore that person and warn others against following him or her. If that person claimed to be a Christian but falsely prophesied, then we who are in Christ were to treat that person as an unbeliever and avoid his or her teachings.

Now that Joe Biden has officially been inaugurated as President of the United States, several people who have publicly claimed that God specifically told them that Donald Trump would serve a second consecutive term as President have been proven false. Either they were lying or they were mistaken.

My question is, can we still consider people like this as brothers and sisters in Christ?

There's this one Bethel pastor who publicly apologized for being wrong about what he thought he heard from God. It's good that he owned up to it, but he actually says in the clip that it "doesn't make me a false prophet." Really? I thought that prophesying falsely was the very definition of a false prophet. I don't see any evidence in Scripture of someone prophesying falsely once, and then prophesying correctly later (except for the times that the Holy Spirit actually gets pagans to prophesy for God). So my gut reaction to someone like this pastor is that he should step down from leadership and never prophesy again because he has been disqualified. Is that too harsh?

And as for those who don't own up to their false prophecies and keep on saying that God told them things, do we consider them heretics?

Of course, if you're a cessationist, then you probably think they're all misguided at best and heretics at worst. I'm open to the idea that the gift of prophecy continues, but I'm super cautious whenever I hear anyone say they have it.

Lots worth touching on here. Great topic!

From my understanding, a Heretic is a believer who goes so far as to say something that distorts the core elements of the faith in a way that would prevent people from coming to saving faith in Christ. But someone with better knowledge of the term's use is welcome to correct me.

But is someone who gives a false prophecy without owning up to it still a brother or sister in Christ if they otherwise still believe in the core gospel? I think so. They are still an adopted child of God. Just a wrong adopted child of God, or at worst a lying child of God. I've been both of those. And I don't believe I lost and later regained the gift of adoption and eternal life because of those times of unrepented sin. But that has more to do with my view of justification/eternal life than it does my view of false prophets in the church.

That said, I definitely think someone who is a ministry leader and gives specifically predictive prophecy (prophecy is not by definition predictive) as a part of their ministry needs to step down the first time it doesn't come true. That indicates a severe problem in their ability to discern truth from falsehood, and someone with that trait should not be teaching others.