“There are three things, young gentlemen, which you are constantly to bear in mind. Firstly, you must always implicitly obey orders, without attempting to form any opinion of your own respecting their propriety. Secondly, you must consider every man your enemy who speaks ill of your king; and thirdly, you must hate a Frenchman, as you do the devil.”

As quoted in A Galaxy Not So Far Away : Writers and Artists on Twenty-five Years of Star Wars (2002) by Glenn Kenny, p. 99

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.

This is sometimes attributed to Sun Tzu in combination with the above quote, as well as alone, but it too has not been sourced to any published translation of The Art of War, though it is similar in concept to his famous statement in Ch. 3 : "It is said that if you know your enemies and know yourself, you will not be imperiled in a hundred battles..."
Misattributed

Source: Acheron

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 108.

Source: The Tenant of Wildfell Hall (1848), Ch. VI : Progression; Gilbert to Mrs. Markham

40
Ki Sayings (2003)
Context: !-- People who are fast learners tend to pick things up so quickly that they lose out on the opportunity for repetitious learning. --> Even if you learn something quickly with your conscious mind, you will easily forget it after you stop practicing. That which is learned with the subconscious mind is not easily forgotten. Therefore to learn something with the subconscious mind, requires months and years of training. Just because you were able to do it before, do not assume that you can do it as well the second time. Each time you do something, you must return to your beginner’s mind, and give it your best.