In our sinful world, evil is everywhere.  Evil people with evil intentions do bad things, and we are harmed by them.  But we all know that our old nature is also still capable of harming others by evil words and deeds.  That is why we need to learn how to follow Jesus (be a disciple) because, without the direction of Scripture, we will naturally take revenge and add to the evil around us - while we claim to be dealing with the evil.

The Divine principle is that only God can properly judge all the wrongs and establish what is right (Deuteronomy 32:35). Revenge wrongly assumes that we have the authority to do God's job.  However, we can never judge with perfect justice because we do not know all the facts or the motives which lie behind the actions.  So, we need to commit the matter into the Lord's hand and trust Him to do what is right.  

Of course, every society has the responsibility under God to restrain offenders (Romans 13:1-5); church leaders and parents must also exercise discipline to guide the individual and protect the family.  But at a personal level, love is the guiding principle, especially towards those who hate us (Luke 6:27-31).  Doing good to those who want you out of the way, is the way Jesus lived and died.  He is our model.

As God sends the sun and the rain to provide food for both good and bad people, our responsibility is to continue to meet the real needs of those around us (Matthew 5:45); not discriminating between those who are nice to us and those who are nasty.  As we do so, we are not condoning their sin or encouraging them to sin more ... rather we are giving them an opportunity to repent or to more fully expose their wickedness.  So when the temptation of revenge rises in our hearts, let us remember how good the Lord has been to us, even though we still sin; and how He cares for all that He has made (Psalm 145:17).  Then let us find a way to serve them in His Name.