“Virtues” are attitudes, dispositions, or character traits that enable us to be and to act in ways that develop this potential.
The reason for a virtuous life does not necessarily depend on belief in rebirth or retribution, but instead on mental well-being acquired through overcoming greed, hate, and delusion.
Suppose you are a drug dealer or sell alcohol (or any self-harm-based tool) … to you, it is just making a living, yet this causes the suffering and mental destruction of people. It is you participating in the destruction of your brothers and sisters. Do we need to believe in karma or the law to come to those conclusions?
Some jobs are built firmly around “marketing” it feels so innocent. Another “job” yet again you are participating in self-harm because you cannot step on others on your way up, at least not when it comes to this level and this perspective. But often it appears that it is possible because we do not see the full picture until it is too late.