Iain Provan says that in the Old Testament, being good is fundamentally about right relationships.
Well, the good life in Israel was defined fundamentally by the character of the God that they believed in, so to be good was to be like God – character-wise, not in other respects, but that’s what it fundamentally meant to be good. And then there were lots of individual aspects of what that looked like. So when the Old Testament has God saying to his people, “Be holy as I am holy”, that’s the fundamental idea.
In that context, to be good is fundamentally characterised by what we might call love – although in modern parlance that word has connotations that we’d want to explore. But loving God, loving your neighbour, seeing yourself as tasked with looking after the rest of creation. So it’s about right relationships. Fundamentally, that’s what good means, it means to be in right relationships.