In II Samuel 4:8, we read of two men who killed Ishbosheth (Saul's son) and brought his head to David hoping that David would reward them for it. But David was so angry with them that he commanded that they be killed immediately. David believed that vengeance belonged to God and he would never take vengeance himself or permit anyone else to take it.
This is an important principle that we must remember at all times.Romans 12:19 is very clear on this. God does not need our help to administer justice or to take vengeance. What would you do if somebody fell down at your feet to worship you? You would do what Peter did - lift him up and say, "Don't worship me, worship belongs to God." Just as much as worship belongs to God, vengeance also belongs to God? When we try to take revenge on someone, that's not any different from accepting worship. We have no more right to take revenge than to receive worship. Whatever harm anyone may have done to us, we must leave it to God to deal with him in His own way and in His own time. We must not even desire anything evil for that person.
When we serve the Lord, we will come across other believers who speak evil of us or try to destroy our ministry. I have discovered that we cannot serve the Lord effectively, without having many people speaking evil of us, spreading false stories about us, accusing us of teaching false doctrine etc. We will then be tempted to take revenge on them. We must resist that temptation firmly. Leave them in God's hands. The Bible says that there is only one Judge who has the right to destroy (James 4:12). So we must leave their fate in the hands of that one Judge.
If the Lord has anointed you, no-one can destroy your ministry, because it has come from heaven. Many people accused Jesus and Paul of being false teachers. Jesus was even accused of casting out demons by the power of the prince of devils. But Jesus never wasted His time answering them. The sincere were not led astray by such false accusations either. Only the insincere went astray.
We read in James 2:6 that rich believers were oppressing poor believers in those days and personally dragging them to court. This is unbelievable. But it is happening today too! One has to be both rich and wicked to drag another believer to court. It is amazing how blind believers can be. Paul says in 1 Corinthians 6 that the same thing was happening in Corinth. Such rich believers have not understood that there is only one Judge who has the right to judge and take revenge. They are sitting on God's throne. So Paul warned them that those who do such things will never enter God's kingdom (Read1 Corinthians 6:9 in the context of the first 8 verses). If someone has done wrong to you, hasn't God seen that? Isn't He able to deal with that person? If you believe that and you believe in an Almighty God, then leave it to God to deal with him.