Look to Greek philosophers for guidance. While for Plato and Socrates, knowing the good was sufficient to doing the good, for Aristotle, there must be, in addition to knowledge, deliberate choice.
Most of us today know what is good, right, honorable; we simply choose to ignore it—by minimizing the issue or impact, rationalizing our (or others') behaviors, creating a new story around the issue that makes us feel good, intending to change the situation then doing nothing—and a dozen other ways we convince ourselves that we're doing the right thing, when we're not.
These behaviors give us an 'out' from tough situations and tough calls. They also make us weak, chip away at our self-respect, and make us susceptible to others' influence.
Meaningful work—ethical work—is hard work that requires each of us to be radically honest with ourselves and our intentions—we must ask ourselves, 'What is the likely outcome for the other party(ies)? Will they experience loss or harm in any way? Will their trust in me/my employer wane? Are there other avenues to pursue? Think really hard about the outcome for others. If it's negative, think again about motive—yours or the colleague asking you to take a specific course of action. More often than not, when harm to another human is involved but another path is possible, the motive is suspect at best and self-serving at worst.'