The last line of the Gospel is off-putting. How are we expected to be perfect? Maybe we don’t even want to be perfect, to be goodie-goodies. Our Lord’s advice becomes more palatable if we note that what Matthew wrote, and what Jesus said, was a little different. The advice was not to be perfect, but to be complete, well rounded, not one-sided.
In my limited experience, Our Lord is alone in telling us to love our enemies. In Korea I became an admirer of the Confucian way of life. I particularly enjoyed standing on the church hill, and looking down on the thirteen hundred kids in the public school yard. Mornings, the principal would stand on a platform, pleading with the children to follow the moral teachings of Confucius.
That moral code was quite specific. It outlined the duties that fall to us in our relationships. There are five sets of duties: those between parents and children, siblings, husbands and wives, teachers and students, subjects and kings.
Where Confucianism falls short of Christianity is in that it puts no bounds on the way you treat unattached persons. People wisely avoid doing business with anyone who might blithe fully cheat them.