A scholar from the last century once asked his pupils, “Is the universe a friendly place?” The response was supposed to provoke the listener to examine his or her own assumptions or worldview regarding ones relationship with his fellow man.
For example, on the one hand, if the universe is “unfriendly,” then ones interest will tend to be more exclusive, and thus tends not to include the wider interests of others, because the focus is on self. The world is bad, and therefore everyman has to watch out for himself. You sink, and I swim. I defy my conscience for self-preservation.
On the other hand, if the universe is “friendly,” then ones self-interest will tend to be more inclusive, i.e., one would tend toward including others into the sphere of ones own self-interest. What hurts you will hurt me. If I sow evil, I reap evil. If I help you, you will help me. I validate my conscience for self-preservation.
When you peel the onion back, the principles of ethics tend toward the latter view, which is to consider and include the interests of others within ones own sphere of self-interest. Thus behavior is ethical.
What is sometime left out of the equation is the effect that ethics (or lack thereof) has on ones reputation. Those who consistently practice ethical behavior engender for themselves the reputation which others should respect and hopefully emulate.
In this sense, our “ethical legacy” is to leave the world a better place than we found it, because we assume that “the universe is a friendly place.” That is, we will not contribute to the problems of the world, but we will mitigate them, because our core assumptions are to love our neighbors as ourselves. Thus we pursue success with significance, because the interests of others are assimilated into our own. In the end, what goes around really, in fact, is what comes around.