I combined vs. 14 with 17-21 because they really deal with one theme: How do we deal with those outside the Church, especially those who are hostile to us?
First off, we need to “bless those who persecute [us]; bless and do not curse.” Of course, here he’s echoing our Savior, always a great policy. Our Lord told us
You have heard that it was said, ‘Love your neighbor and hate your enemy.’ But I tell you, love your enemies and pray for those who persecute you, that you may be children of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. If you love those who love you, what reward will you get? Are not even the tax collectors doing that? And if you greet only your own people, what are you doing more than others? Do not even pagans do that? Be perfect, therefore, as your heavenly Father is perfect.
When someone hurts us, our response is not to hurt back, nor even to passively receive it (like Buddhists). Our response is to bless them. To pray for them. To try to do good for them. In this we’re displaying a family likeness to our Father, who pours sunshine and rain on the good and the bad.
Next we’re told to “Be careful to do what is right in the eyes of everyone. If it is possible, as far as it depends on you, live at peace with everyone.” I think those two verse are related, though not repeating each other. It’s not enough to have peace with God and be in a right standing with the Almighty. That’s the most important thing, but it’s not the only thing. We need to, as much as possible, have a clear conscience with outsiders. That means we’re scrupulously honest in our business dealings with them. That means we try to get along with them as much as possible; if you’re a believer and are looking for a fight, then pick your fights in the spiritual realm (where it really counts), not here.
But please notice that he gives a very important caveat here: “If it is possible, as far as it depends on you,” live at peace with everyone. Despite your best efforts, some people you’re not going to be able to get along with. But if there’s an ongoing conflict and animosity, it’d better be coming 100% from the other side, not from ours.
And once again we see a wonderful truth, one in the light of which we’re supposed to live (sorry for the convoluted grammar): God is the Judge of everyone, and—outside of his grace—will give everyone what they deserve. That’s his job, not yours. Your job is to pray for them (if they’re truly persecuting you, they certainly need it), do good for them, relay to them the Message about salvation in Christ, and live at peace with them as much as possible. Don’t try to avenge yourself, let your Father handle that. I promise he’ll do a much better job than you ever will. Of course, by doing this, once again, you’re imitating your Savior: “When they hurled their insults at him, he did not retaliate; when he suffered, he made no threats. Instead, he entrusted himself to him who judges justly.”
If the tables are turned and your enemy finds himself hungry, you’re supposed to feed him. If he’s thirsty, give him something to drink. But what in the world is Paul talking about when he says treating our enemy like this will “heap burning coals on his head”? There are two explanations for this: A) By doing this, you’ll heap the burning coals of judgment on his head. If you treat him like this and he continues to persecute you, he’s adding judgment upon judgment upon himself. Or it might be B) an ancient Egyptian custom in which a person who wanted to show public contrition carried a pan of burning coals on his head. The coals represented the burning pain of his shame and guilt. In other words—and this is the best-case scenario—your Christ-like response to them might lead them to repentance. To paraphrase Abraham Lincoln, all of God’s (and our) enemies will be destroyed, but his preferred method of destroying them is by turning them into his adopted children. Then they’re no longer your enemy; they’re your sibling in Christ. Either explanation works and is consistent with Scripture, but I prefer the second one.
The final command in this (long) list of commands in chapter 12 really crystallizes how we’re supposed to respond to people on the outside: “Do not be overcome by evil, but overcome evil with good.” My friend, if an enemy persecutes us and we use the weapons of the world to strike back at them, then we’ve already lost. If an enemy persecutes us and we respond in a Christ-like way--entrusting our Father to defend us as he wills—then we’ve already won. Whether they repent or not, we’ve overcome the real Enemy on the real battlefield.
And that’s a good thing.
Father God, so often I fight battles I’m not supposed to fight, or I fight them using my way instead of yours. From now on, by your grace, I intend to follow the footsteps of my Savior, letting you do what you promise to do, while I do what I’m supposed to do. Doing things your way instead of mine is the only way to go.