There is no doubt that this is a challenging teaching. Let me go into it slowly, beginning with the notion of “hate”.
As you said, Mike, the Hebrew Bible doesn’t enjoin us to hate our enemies, but I doubt Jesus has the Bible in mind here. He is living under brutal Roman oppression, and may well be addressing the hatred Jews have of their Roman occupiers. Translating his teaching into our time would be as if Jesus were calling us to love the Taliban and Osama bin Laden.
And then there is the question of Luke 14:26, “Whoever comes to me and does not hate father and mother, wife and children, brothers and sisters, yes and even life itself, cannot be my disciple.” And John 12: 25, “Those who love their life, lose it, and those who hate their life in this world will keep it for eternal life.” In these passages Jesus seems to be obligating his followers to hatred. How are we to understand this?
Then there is the notion of “love”. Is Jesus talking about feeling loving toward our enemies? Or, in good Jewish fashion, is he talking about acting lovingly toward them? For example, Exodus 23:4 commands that if you find your enemy’s ox or donkey you have to return the animal to him or her regardless of how you feel about the person. Since we cannot control our feelings— indeed by the time we recognize that we have feelings that might need controlling we have already felt them— there is no point in commanding certain feelings. But we can control our behavior. Hence Proverbs 25:21, “If your enemy is hungry, give him bread to eat; and if he is thirsty, give him water to drink.”
But I may be too narrow in my thinking. Proverbs 24:17-18 does seem to speak to feelings: “Do not rejoice when your enemy falls, and do not let your heart be glad when he stumbles,” so maybe there is a way to control our feelings even if I can’t find one.
And then there is “pray for those who persecute you.” This, too, is found in the Torah Jesus learned. Moses prays for Pharaoh five times (see Exodus 8:24-27, for example); Job prayed for his enemies (Job 42:9), David prayed for Saul (I Samuel 24:12), and Jeremiah urges the Hebrew people to pray for the Babylonians (Jeremiah 29:7).
My point here is simply that Jesus is not inventing a new way of living, but rather gathering threads from his Jewish culture to weave a new Judaism bearing his special emphasis.
It is Jesus’ last admonition—“Be perfect as your heavenly Father is perfect”—that I find the most challenging. You are taking this to be “mature” or “complete,” by which I guess you mean something like “be consistent in your loving actions toward your enemies, as God is consistent when He shines the sun upon the good and the evil alike.”
If this is what Jesus means, then I think we can all work toward this level of moral consistency. But what if he does mean something more? What if, as you say, “perfect” means “complete,” and “complete” means “whole,” and “whole” means inclusive of opposites?
God seems to have a light and dark side. He can be loving and wrathful. The mere fact that there is a Tree of Knowledge of Good and Evil in the Garden of Eden suggests that there must be some evil to know. Where could that come from if not God? God is the source of all reality, and reality is comprised of opposites: up and down, in and out, right and wrong, good and evil, mercy and judgment, etc.
Being made in the image and likeness of God, we, too, have these opposites embedded in us. To be perfect, whole, complete, is to recognize what Judaism calls our Yetzer haTov and Yetzer haRah, our innate capacity for good and evil respectively. According to the rabbis both capacities are necessary for human life and flourishing. Evil, rooted in concern for the self, is the yeast that motivates us to marry, raise a family, and run a business. It is called “evil” because if taken to extremes, that is if left untempered by our capacity for good, it can lead to terrible abuses in marriage, family rearing, and business practices.
Similarly the capacity for good is rooted in selflessness, and, unless balanced by the capacity for self-focus, leads to loss of self and failure to achieve anything of value to regarding oneself or one’s community. To be a successful human each inclination must be yoked to the other. In effect, the Yetzer haRah is the energy for doing, and the Yetzer haTov is the direction that insures our doing is for the good.
Maybe we can understand Jesus’ command to be perfect to be a call to recognize our dual nature and place rah in service of tov, just as God softens His judgment with His compassion.