It is not merely true that a creed unites men. Nay, a difference of creed unites men - so long as it is a clear difference. A boundary unites. Many a magnanimous Moslem and chivalrous Crusader must have been nearer to each other, because they were both dogmatists, than any two agnostics. "I say God is One," and "I say God is One but also Three," that is the beginning of a good quarrelsome, manly friendship.
A drop of honey catches more flies than a gallon of gall. So with men. If you would win a man to your cause, first convince him that you are his sincere friend. Therein is a drop of honey which catches his heart, which, say what he will, is the highroad to his reason.
We rejoice in the joys of our friends as much as we do our own, and we are equally grieved at their sorrows. Wherefore the wise people will feel toward their friends as they do toward themselves, and whatever labor they would encounter with a view to their own pleasure, they will encounter also for the sake of their friends.