If a person loves truth and believes his religion is true then it is natural to defend truth against error and want to destroy error, that which is false. Another way to put that is if one loves truth one must hate error.
There is only one reason to belong to any religion, or Christian denomination. That is you believe its doctrines to be true.
When Christians who are divided, because they believe contradicting doctrines, dialogue or interact about religious matters, the interaction could either be acrimoniious and full or rancor, or it could be in humility, kindness and love.
Either way both parties could be well intentioned toward the other. If a Mormon wants to convert me to Mormonism it is, because he believes his religion is true and wants me to have the benefit of the good he believes I will find there. He does not want my harm, but my good.
Implicit in the conversation would be the fact that we both believe what the other believes is false.
I am Catholic, because I believe the doctrines of the Catholic Church are true. Implicit in that statement is I believe Protestant doctrines, whatever they are, and I realize there is no one body of doctrine all Protestants hold, but they are in disagreement with one another on many things, are false.
Why is it so important that what we believe doctrinally is true, that our beliefs are in harmony with spiritual truths? Believing error leads to harm, great harm. The foundation if western civilization is Christianity, the Christian religion. The reason there are so many social ills, epidemic divorce, addictions, perversions, violence, decaying cities is our civilzation has abandoned the fundamental understanding of truth revealed by God and become secular. In fact it has banned Christian religion from the public forum thinking that God Himself has no right to impose His law on His people.
How did this happen? It came about, because of disunity and confusion about spiritual truths, and that is the result of the fracturing of Christendom into thousands of seperated pieces, against the commandment of Christ that His disciples be one, and of Paul who commanded us to be of one mind and agree on all things.
This is the consequence of error. It is a disaster for the Church and Christian people. The Lord’s vineyard is ravaged.
The remedy for Christian disunity is not hostility. It is following the commandments of Jesus when He rells us to love one another and pray for one another.
Nevertheless we should hate error and seek truth.
I am not offended when Protestants believe or assert that Catholic doctrine is false. If they did not believe that they would be Catholic. It is nothing personal. A Baptist minister told me no denomination has all of its doctrines correct. This man councilled young women that it was ok to abort their babies. He said any denomination that asserted all of its doctrines are correct is arrogant. This is not only against what Jesus promised in scripture, to lead His Church into all truth, but it is irrational. I asked him which of the doctrines he and other Baptists believe are false. At first he looked at me as if I were an idiot. He said if he knew which of his doctrines were false he would not believe them. I said, if you do not know which of your doctrines are false, but do know some are, then neither do you know which are true. This is confusion. Yet he sets himself up as a shepherd of souls and he admits he does not know what truth is.
When we discussed truth, he condescendingly said my Church believes it knows truth. I agreed. He said my Church thinks it knows truth. I agreed. he said my Church says it knows truth. I agreed. He becamse exasperated. He said what is truth. I said ask Pilot. If you don’t know and are a spiritual leader how can you guide people?
I do not hate this man, or despise him. His religion and he have caused harm to souls. Of course he claims the doctrines of his religion are all from the Bible. My hope for him is the same as my hope for myself, that we both find mercy, but he believes he has a lock on it.