Human coexistence is extremely fragile and threatened with failure. Elementary experiences of violence and injustice make this clear to us. Yet man was born to live together. John Calvin emphasized this almost 500 years ago. The lawyer Johannes Althusius agreed with him a little later and emphasized that politics is about the art of symbiotic coexistence. With this objective, both reformed thinkers of political ethics have shown the way. To this day, their vision of successful coexistence still provides orientation in the face of current challenges. For the sake of the future, the memory that Marco Hofheinz practices with his theological-historical studies on Reformed ethics is necessary.