I am not Christian, However, I like to quote Jesus on occasion. "Love thy enemies" he said. Why? Especially in Jesus' time when barbarity, was high in popularity.
Let's face it, the reason someone is an enemy is because that person is an a-hole. But for some strange reason, that person thinks you are an a-hole, and that's why he treats you that way. I have had people decide not to like me that I had never spoken to.
Is it karma that brings two enemies together? Very possibly, but not for the reason you might think. The logical thought would be that the two souls are old enemies from a past life. The truth is that the two souls are extremely close, so close that one is willing to antagonize the other. In other words, one soul accepts his "role" in order to help his friend soul grow.
In life, friends, loved ones, teachers, clergy, all teach us the lessons we need to learn. But, it is the a-holes, demons, and even Satan, that check to see if you have passed the test. Your enemies are the ones that test your true meddle. They are as important to your overall spiritual growth as the teachers, and Saints.
In the grand view of God we are all one, and helping each other evolve up the spiritual scale.
Want to learn more about how souls take on various roles in your life? Click here