Jealousy is culpable for more church splits than doctrinal differences. People may dress up their disagreements in doctrine but the naked truth is that they simply do not like the other person and/or group. Once jealousy has taken root it is very difficult to weed out.
Envy is not jealousy. Envy is wanting something that you don't have. Jealousy is hating the person for it. Feeling that you deserve something, or that another person does not deserve something, or that you are better than someone could all be sources of jealousy. For example; A co-worker is promoted above you and you think that they are not deserving because you could do the job better than them. Jealousy is to continually look for ways to make that person look bad, pointing out all of their mistakes, or always trying to one-up them.
In the church jealousy is no different and when it is present there is destruction. James tells us that, "where jealousy and selfish ambition exist, there will be disorder and every vile practice (James 3:16)." Jealousy leads to disorder in the church because everybody is trying to do things their own way. They want to make themselves look good and the other person look bad. Even if there was a path to make things work they would never allow themselves to walk down it together. The jealousy between people (or groups) causes more collateral damage then it achieves its mark. It is like trying to hit a piñata with a blindfold on inside of a china shop. Each swing rarely does any damage to the piñata but breaks all the fragile things around it. The jealous between two people can destroy a church.
We are all capable of jealousy and we should examine our lives to see if there is any fault in ourselves. Do you constantly talk bad about someone? Do you try to make yourself look better than other people? Are you not friends with certain people because everybody likes them? Do certain people frustrate you more than others for no reason?