reap what you sow. In Indian philosophy it’s called “karma”. Good is paid back with good & vice versa. This proves the perfect justice of God.
Sometimes, somebody has either hurt us badly or has cheated us in some form. We feel angry. How do we handle this anger ? For most people there is only 1 way such anger can be handled - they take revenge. Revenge could be in many forms - they could gossip badly about the person, or they may try to harm the career of the person, or they may try & cause physical harm, or they may simply abuse the person on his face. The person taking revenge often feels that now justice has been done by him for the pain caused to him.
However, one can adopt a different road. One can leave the matter to give justice to the wrong doer to God. Because God ensures karmic justice for every individual. When you do this, you rise in your humanity, & you give living proof of your faith in God.
Everyone has to answer their karma : leave it to God !