You have heard that it was said, "you shall love your neighbour and hate your enemy". But I say to you, love your enemies and pray for those who persecute you, so that you may be sons of your father in heaven.
We know that loving our enemies is something we should do. But in reality, despite what we say or admit, we all tend to operate more like the saying that Jesus attacks - loving our neighbours and hating our enemies. Just like the Pharisees we would define neighbour narrowly. We want good things to happen to us and our friends and family and we're happy for the people who've wronged us to get what we think they deserve. Unless it's our friends or family who have wronged us and then our circle of love decreases even more! We have a very selfish view of love that will define neighbour as narrowly as we want and then point inside that circle as an example of how loving a person we are. "of course I'm a loving person, look how well I love my mother... except that time we didn't speak for a year!"
We will always move the goalposts to make ourselves look good, and it's that attitude that Jesus attacks.
Who are the enemies we are supposed to love? Probably the person who popped into your mind when you read the phrase "love your enemies" and thought, "I could never love them". The person who you are trying to justify why this doesn't apply to them. The person who you can't imagine becoming a christian, and actually don't want to become a christian.
What does it mean to love our enemies? We are told in the OT to love our neighbour (everyone) as ourselves.
"you are to have that same totally consuming unfeigned, fervent, habitual, permanent love which brings into your heart their interest, their needs, their wants, their desires, their hopes, their ambitions, and prompts you to do everything you can to make sure that all their welfare, safety, comfort, and interest is met and that whatever they need and whatever they want or whatever pleasure they have, you are anxious to fulfill on their behalf." John MacArthur
It is a high expectation. We are to pray for our persecutors, not against them! This is only possible in God's power. It is only possible through the Holy Spirit. It is only possible because Jesus loved his enemy - me - enough to go to the cross, taking my sin and giving me his righteousness.