“You're the sort of enemy your enemy must love.”

1950s, Loving Your Enemies (November 1957)
Context: Another way that you love your enemy is this: When the opportunity presents itself for you to defeat your enemy, that is the time which you must not do it. There will come a time, in many instances, when the person who hates you most, the person who has misused you most, the person who has gossiped about you most, the person who has spread false rumors about you most, there will come a time when you will have an opportunity to defeat that person. It might be in terms of a recommendation for a job; it might be in terms of helping that person to make some move in life. That’s the time you must not do it.

1950s, Loving Your Enemies (November 1957)
Context: How do you go about loving your enemies? I think the first thing is this: In order to love your enemies, you must begin by analyzing self. And I’m sure that seems strange to you, that I start out telling you this morning that you love your enemies by beginning with a look at self. It seems to me that that is the first and foremost way to come to an adequate discovery to the how of this situation. … some people aren’t going to like you. They’re going to dislike you, not because of something that you’ve done to them, but because of various jealous reactions and other reactions that are so prevalent in human nature. But after looking at these things and admitting these things, we must face the fact that an individual might dislike us because of something that we’ve done deep down in the past, some personality attribute that we possess, something that we’ve done deep down in the past and we’ve forgotten about it; but it was that something that aroused the hate response within the individual. That is why I say, begin with yourself. There might be something within you that arouses the tragic hate response in the other individual.

1950s, Loving Your Enemies (November 1957)
Context: Now there is a final reason I think that Jesus says, "Love your enemies." It is this: that love has within it a redemptive power. And there is a power there that eventually transforms individuals. That’s why Jesus says, "Love your enemies." Because if you hate your enemies, you have no way to redeem and to transform your enemies. But if you love your enemies, you will discover that at the very root of love is the power of redemption. You just keep loving people and keep loving them, even though they’re mistreating you. Here’s the person who is a neighbor, and this person is doing something wrong to you and all of that. Just keep being friendly to that person. Keep loving them. Don’t do anything to embarrass them. Just keep loving them, and they can’t stand it too long. Oh, they react in many ways in the beginning. They react with bitterness because they’re mad because you love them like that. They react with guilt feelings, and sometimes they’ll hate you a little more at that transition period, but just keep loving them. And by the power of your love they will break down under the load. That’s love, you see. It is redemptive, and this is why Jesus says love. There’s something about love that builds up and is creative. There is something about hate that tears down and is destructive. So love your enemies.

Spiritual Sayings of Kahlil Gibran
Paraphrasing of Gibran's quote "My enemy said to me, 'Love your enemy.' And I obeyed him and loved myself."
Variant: And God said, Love your enemy, & I obeyed Him & loved myself.
Source: misattributed on these websites: GaiamLife (blog) http://blog.gaiam.com/quotes/authors/kahlil-gibran?page=3 & Quote Corner - Khalil Gibran quotes Part 1 http://quotecorner.com/Khalil-Gibran-quotes.html

Source: Choke

Source: The Princess Bride

Poor Richard's Almanack (1756); this has also been quoted in a paraphrased form used by Bill Clinton in [ 1998 address to Beijing University http://news.bbc.co.uk/2/hi/asia-pacific/122320.stm, as "Our critics are our friends, they show us our faults".
Poor Richard's Almanack

Source: The Exiled Queen