[yuān yuān xiāng bào]   

冤    冤    相    报    冤：冤仇；报：报复，报应。佛家语，认为冤仇总会有报应。 贬义>

比喻与人结冤仇终会有报应，也指仇人互相报复。

Their mutual injuries were avenged on each other

冤家对头    冤天屈地    冤家路狭    冤沉海底    冤冤相报