As Scott Cunningham says in Cunningham’s Encyclopedia of Magical Herbs:
Magic is love. All magic should be performed out of love. The moment anger or hatred tinges your magic you have crossed the border into a dangerous world, one that will ultimately consume you.
Biding the Rede is the only thing you have to do to be Wiccan. Do no harm. That is the essence of the Wiccan faith, our one law. No one imposes this on us. A Wiccan is a witch who chooses of his or her own free will to be bound by this law. We see life as magickal and magick as sacred, so Wiccans are white witches who do not hex or harm.
To assume that white magick is less powerful than black magick would be to mistake kindness for weakness. Certainly we defend ourselves, but we generally do so by deflecting attacks rather than by attacking
Magick itself is neutral, a tool. Like a hammer, it can be used to smash or to build. It is colored by your intent. White magick is a term used to describe that which is positive, constructive, or helpful. Black magick is that which is negative, destructive, or harmful. If you have a business and you work spells to make it prosper, that’s white magick. Casting spells to destroy your competition would be black magick. These are not racial terms. The terms good and evil, or dark and light, are often used to express this same concept.
Why black and white, and not some other colors? To answer this question you have to go back into prehistory and imagine how terrifying the night was for humans before we learned to use fire. The black of night was full of unseen threats, a dangerous time that you might not survive. The white light of day brought illumination and safety, welcome relief.
White magick is the right-hand path, black magick the left. The symbolism of right and left is also very ancient. The right hand was used for eating, the left hand for bathroom functions. Imagine life without toilet paper and you’ll understand why it’s customary to shake hands with your right hand! This has nothing to do with being right- or left-handed. It does, however, explain why, in the past, left-handed people were often forced to learn to write with their right hands.
The term green witchcraft is sometimes used to describe Celtic magick, fairy magick, Earth magick, or any combination of these. There are several theories of “gray magic,” but I think gray magic is what Hindus call maya illusion.
Do murderers balance nice people? Do child abusers balance loving parents? If they create balance, does this excuse their crimes? Try telling that to a judge! “Well your honor, I only stole that car to create balance in the universe.”
There is another polarity theory, which states that if you do two hexes and two healings, they balance one another or cancel each other out. Although there may be some logic to this, it’s still just a self-serving excuse, a way to delude yourself that you are a white witch when you practice black magick.
Some traditions hold that those spells you cast on yourself constitute white magick, while those you cast on others constitutes gray magick. I think a spell that harms you or anyone else is black magick; one that helps or heals anyone, including yourself, is white magick. There is no gray in this area as far as I am concerned. Being of service to people in need or distress is one of the things witches do best. I therefore see nothing wrong in casting spells that help others, with their permission, of course.
Some witches argue that there are evils too great, situations too grave, to be handled with white magick. The end justifies the means, they say, making black magick necessary for the greater good. Although there is some merit to this argument, I have never encountered a situation I couldn’t handle with white magick. Binding, banishing, and transformation are the powerful tools of a white witch.
There are excellent moral and ethical arguments against practicing black magick. If you are not convinced by those, however, here is a practical one:
What goes around comes around.
Everything we put forth is eventually returned to us. Moreover, Wicca recognizes the Law of Three, which states that this return is triple. Black magick may provide instant gratification, but it ultimately does you more harm than anyone else. Many white witches have learned this lesson the hard way.
Carefully examine any spell or magickal working before you perform it to be sure that it is in accord with Wiccan law. Ask yourself if you are casting the spell for the person, or on the person. If you do harm inadvertently, try to right it. Many witches work a phrase into their spells that prevents accidental harm, something like, “And let no harm be done by this.”