I attend a Baptist church and I am a former Catholic...
On a different Christian Forum, I made friends with a fellow who was in this situation. He was very upset by the error he was taught in the Roman Catholic Institution.
There is a term called, "damnable heresy." These are things that, if you believe them, you are not a true Christian. Also, things that MUST be believed, but are NOT, can be included. Mostly, a Church will list some obvious ones, but we can be sure the proper list is formed by the LORD Jesus Christ. It is He that knows the hearts, and knows where our affection and allegiance is centered.
If we are part of ANY denomination that holds to error that turns a person's heart AWAY from the true worship of the LORD, we may be sure that believing those heresies has kept us from what we profess to seek.
It may be helpful to answer what things we KNOW are in the category of "damnable heresy." It will be different list depending on the denomination. The Catholics will certainly consider that a Baptist is not a Christian because he rejects a list of certain beliefs, and a Baptist will be as certain about a Catholic for the list he maintains.
The list maintained by a Catholic may not be truly a list of "damnable heresies," and some things a Baptist (even depending on which actual Church he attends) puts on a list may not be purely accurate.
Let us start with JUST ONE of the beliefs that a Catholic holds (if he follows the teaching of the Roman Church,) and that would be TRANSUBSTANTIATION. The original laws of the Roman Catholic Institution were used to justify the killing of millions of people who did not believe this basic principle. It is simply that they believe the actual body and blood of their God is present in the bread and wine, and any who do not hold that belief, and WORSHIP THESE AS GOD are heretics. (see Second Commandment)
Exodus 20
4 Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth:
5 Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;
6 And shewing mercy unto thousands of them that love me, and keep my commandments.
Some of the other denominations in your list may hold to this as well. The Catholics in America are not so sure about this, and I have not met any who would say they believe that dogma. Typically, I'll tell those people that they are not Catholic, but Protestant, because of that.
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