Jude gives us insight into who causes divisions and how the church should respond:
Jude17 But you must remember, beloved, the predictions of the apostles of our Lord Jesus Christ. 18 They said to you, “In the last time there will be scoffers, following their own ungodly passions.” 19 It is these who cause divisions, worldly people, devoid of the Spirit. 20 But you, beloved, building yourselves up in your most holy faith and praying in the Holy Spirit, 21 keep yourselves in the love of God, waiting for the mercy of our Lord Jesus Christ that leads to eternal life. 22 And have mercy on those who doubt; 23 save others by snatching them out of the fire; to others show mercy with fear, hating even the garment stained by the flesh.
1. When unbelief arises and people stand out who scoff the truth, it is the not person who cries "foul" who is the divisive one but rather the person who hit the ball. The scoffer following ungodly passion--the person not holding to the faith given the saints once for all or the person not practicing biblical piety--they are causing the division. They are devoid of God's Holy Spirit.
2. The person who sees this however, is supposed to people careful that they keep themselves in the love of God. They should watch their own doctrine so that they do not become a scoffer, they should also watch their practice. We must continue to wait for God's mercy. This means we should not become self-righteous about pointing out divisive people when we must. We must point it out, but we do so in view of God's mercy that we've received from Jesus and not with haughtiness.
3. Undoubtedly when scoffers arise there will be those who are tempted to jump on the bandwagon. There will be a third category: the person that begins to doubt. We who are remaining in the love of God are to be merciful towards them. We understand their struggle and we lovingly point them back to the truth while we recognize the reality of their doubts. We also need, I think, to recognize that doubt can be existentially hard on a person. Here we can graciously assure them of God's truth, God's love and God's grace. You don't shoot a sheep that is wounded, you shoot the wolves and nurse the sheep back to health.
4. We are to show mercy by snatching others out the fire. We get them at the last minute as it were. We point out their grave error in a loving manner. But when we contend for the faith and proclaim the THE faith, when they turn through the Holy Spirit's use of the Word of God, they have been reclaimed at from the fire itself. It is entirely proper to point out the errors of a person in order to save them from the fire when we have the authority of God's Word to tell us what an error is.
5. Finally we can show mercy to the person stuck in sin at the same time we hate the garments stained with sin. Some "Christians" are entirely vindictive against the sinner or the Christian stuck in sin. They will jump to conclusions about the persons eternal state. Some "Christians" feel that any mercy towards a struggling sinner is somehow capitulating to the flesh and wickedness of sin. Jude tells us that opposite. Our Lord Jesus shows us the opposite.
The Book of Jude shows us that we can handle the divisive divider and love orthodoxy. It is the one who departs from orthodoxy first who is the divisive one not the person who comes along and say "whoa wait a minute." A passion for orthodoxy, a nose for the real (not imagined) heretic, hating and a merciful heart are something that should be united by God's Spirit in the heart of all who are in union with Christ.