Adam Smith's Theory of Moral Sentiments

The world would be a better place if everyone operated under the premise that they shouldn't export pain from people closer than those far away. But still in the back of my mind, there's this thought of some kind of Adam Smith idea: Maybe it's not the worst for everyone to pursue their own best interests and things might work out in the end. I think Smith is talking about different things there, and I think he's not talking really ethics.