bèi àn tóu míng
背:背弃;投:投奔。指背离黑暗,投向光明。比喻背离昏主,投向明君
元 尚仲贤《单鞭夺槊》楔子:“贤臣择明主而仕,背暗投明,古之常理也。”
背暗投明作谓语、定语;指追求真理。
leave the darkness and come to the brightness--quit the illegal associations and activities and return to lawful life