I believe if a judgement were to come up where you had to go to jail would you want mercy to be shown to you? If someone were to take your stuff wouldn’t you want it back? I believe we have to realize the answer to that question before we get to the scenario. We should always be kind to one another. Being nice may seem weaker than being evil, but we have to realize who is really in charge. The righteous God has put Jesus Christ in charge of the entire universe both heaven and earth. So we are really trying to please the Lord when we make a decision.
When God said to treat others how we want to be treated He was serious and talking about how we sometimes tend to treat people poorly but expect others to treat us well. Just because you’re rich doesn’t mean you should be treated better than a poor person. Love does no harm to a neighbor. And when Jesus gave the parable of the man who fell into the hands of robbers, the man was helped by his enemy rather than his own people. We should keep in mind how we want God to treat us if we were in the shoes of another person. God bless you