This is really "live and let live" in practice.
Harmony can take some work! This is probably one of the areas most of us need the greatest effort.
One of the main causes of conflict on this planet is the inability to apply this concept - especially when confronted with strongly held views, such as religious belief or political affiliation.
To live in harmony, we need to accept that there are other points of view - and be content with that. In return, we get to retain our opinions. It is only by the airing of different points of view that we are able to get a handle on what is real. It is always worthwhile to test our position against that of others.
Another essential aspect to the attainment of harmony is forgiveness. It is sometimes difficult to let go of an affront. If you think about it, why hang onto something so negative that it diminishes you?
One good thing is that the more one practices getting along with everyone despite differences, the easier it becomes. It often helps to try seeing things from their point of view.