"Love your enemies...." comes from which book:
A: The New Testament
B: The Koran (Quran)
If you answered A, you are correct. If you answered B, you are incorrect. Surprisingly the Koran itself has no such ethic of "loving your enemies" or even a general ethic of loving your fellow man beyond fellow Muslims.
But there is an almost universally held notion in popular culture, media, and even among Christians that at root Islam is much like Christianity or even other major religions such as Buddhism or Hinduism.
In fact, the root is quite different. The Western world needs to be aware that at root Islam is very different in it's ethics of love. And only in it's later, westernized forms is it "moderate."
The opposite is true for Christianity. The biblical root commands believers to love all people--even enemies, "live at peace with all men," forgive, never take their own vengeance. The later perversions of Christianity over the centuries have introduced non-biblical values and practices such as the crusades, the inquisition, or justifying aggression, greed, or hatred.
To check this for yourself, do a concordance search for the word "love" in the Koran. Then do it for the New Testament.
In the Koran there are a some mentions of "love for Allah," and a few mentions of "love" for fellow Muslims (the poor among them) but not extending to enemies, or even those who follow other religions and are living at peace. Quite the opposite, in fact.
You can't include successive centuries of Islamic tradition--additional writings. Certainly successive Muslims have added in such ethics at times. But today, there are millions who do not hold to any such ethic in Islamic circles. But outside the middle east you do find many "moderate" Muslims who have added an ethic of love or at least tolerance and non-violence, but have done so in spite of the Koran.