The Witch's/Wiccan Rede: Do what you will and harm none.
The Law of Three: That which you do will return to you threefold.
Almost every single publically available book on witchcraft in it's many different forms will present these two statements as part of the moral code of the craft. Many people take offense to the idea that these two statements are the core concepts, but it seems to be the case from an anthropological standpoint, so I will leave the argument as it is. The matter of traditions vs. popular witchcraft will be discussed at another time.
Returning to the primary target of my typing tonight... the witch's rede and the law of three are important concepts. Though they are frequently misinterpreted. I am presenting this discussion on the topic to help clarify the confusion surrounding these points.
The witch's rede does not permit one to harm themselves. You are a person, you are *some one* and thus protected by the clause preventing harm. Self-defense, however, is not prohibited either. In-action when some one is striving to harm you is acquiescing. You are agreeing to be harmed because you are not putting up any argument or fight to prevent it. If you don't protect yourself, chances are extremely low that some one else will protect you.
Thus, I present the modified version of the Witch's Rede:
Do what you will and harm none, unless it is in defense. When you act in defense, always mind the law of three.
Now, I've done my best to restrain the false archaic quality that many others would affect as they present these statements, but I couldn't help it in the last clause above. You'll see why. First, let me explain that pesky little thing, the law of three.
Some people say very plainly, the law of three is a karmic law. What is a karmic law: it states that all of our actions will return to us in some fashion at a later time. Thus, if you help some one later on down the road, some one else will help you. It's a fairly simple concept. We then add the concept that it will return some multiple of three. Now does this mean that if you proverbially strike some one in the face that at a later time you will be hit in the face three times? Will it be thirty times? Or perhaps three hundred times?
When I was initially practicing the craft, I had a little difficulty with this concept. Then it came to me that it isn't the number of times an action of yours returns to you. It's not even the degree by which it returns to you, it is merely the fact that it does return and it will manifest in different fashions.
Imagine, if you will, that you throw a stone into a still pool of water. The action is throwing the stone in the water. The first return to you is the initial effect of the action; the stone falls into the water. The second return to you is the second effect of the action: the first wave created by the disturbance of the stone's falling. The third return is the long term effects of the action; reflection of that wave off of other surfaces at the edge of the pool. Now, you can extend this analogy out and devise many, many more implications and count the proverbial waves and the effects of the proverbial waves in that pool. I think, however, the three waves demonstrate my vision clearly.
We are free to act in any fashion. Our actions must not harm others or ourselves. We always need to remember our actions have consequences and be responcible for them.