It's been said that without conflict, there would be no New Testament. Out of controversy arose revelation from God. Conflict can be healthy and useful for churches just as it is for any human relationship. It is okay for people to differ with one another. In fact, resolutions for the sake of quick agreement are often worse than agreements that are carefully worked out over time.
Conflict occurs when two or more people have different points of view on any matter.
That in itself is not a sin. Sin enters the picture when we do the wrong things to resolve that conflict. Conflict is not easy to deal with. It is often very hard to control. It is more likely to consume and destroy than it is to save and reconstruct.