Do not say, "I will repay evil";
wait for the Lord, and he will deliver you.
The sense here is not about bringing the wicked to justice, which we are to promote. It is about exacting our personal revenge. This is a proverb for the worker outmaneuvered unjustly for a job promotion. It is for the student who is beat out for an award because of another student cheating. It is for all of us in our daily experiences of being slighted and taken advantage of.
Wait for the Lord. Wait for the Lord because vengeance belongs to him. And it belongs to him because any offense is an offense against him. He alone is the judge, and offense against him is infinitely more serious than offense against us.
Wait for the Lord because he will exact the proper measure at the proper time. We will not. We inevitably sin in our attempt at retribution, and thus end up in the same position as our offenders.
Wait for the Lord for your own peace of mind. Your offender gains even more advantage by your fretting and scheming. You have lost not only the goal the offender won, but your contentment as well. Waiting for the Lord means putting the matter, including the results, in his hands and not worrying about the outcome. That is not only victory but the best kind of payback - not letting your offender take away your peace and joy.
Wait for the Lord for the sake of your relationship with the Lord. How can you learn to trust him if you will not wait on him? How can you learn contentment without waiting on him in all circumstances? How can you experience his working in you and around you if you do not wait for him? Wait for the Lord.