Want a simple explanation that sense restraint is an important aspect of ethical conduct, for a loved one who is not into Dhamma

Could you try to formulate an answer to the above question, in line with the Pali Canon, using simple colloquial language, for someone who doesn't yet know Buddhist terminology? I'm asking because I want to try to explain this to a loved one For a run-of-the-mill sort of person, life would take the path of least resistance and indulgence in sense pleasures is what is long sought. It is the path of least resistance, the downward path or ‘Anusothagami’ while the traveler of this road less traveled is climbing in the opposite direction to the flow or ‘Patisothagami’. How can one get such a person to see this otherness?