Lynn Cohick explains how strange Jesus’ command must have sounded to ancient ears.
When Jesus said “love your enemies”, I think people paused. They may have said, “Wait a minute – can I hear that again? That sounds so odd!” Because, you see, people relied on each other in the ancient world. They relied on their neighbours – sort of the phrase “if you scratch my back, I’ll scratch yours”. And there was limited resources, so you didn’t just throw your extra around, you were very careful with who you helped, knowing that they would help you in return. That means, for someone to say “love your enemies”, that just sounded foolish.
Now that was certainly foolish to the Greeks and the Romans. The Jews, they had in their Scripture teaching that you should take care of the stranger in your midst. The Proverbs talk about, if your enemy needs food, to give him food, or to give him drink. But they didn’t talk about loving your enemies. Jesus goes a step further.
I think Jesus wanted people to think about the category of enemy to begin with. Really, who is my enemy? Is the Roman soldier my enemy? Or is that also a child of God? Is the Samaritan my enemy? Or is that a child of God? I think Jesus was pushing people to even rethink this category of enemy.