Here is some information taken from various sources:
The Rule of Three (also Three-fold Law or Law of Return) is a religious tenet held by some Wiccans. It states that whatever energy a person puts out into the world, be it positive or negative, will be returned to that person three times. Some subscribe to a variant of this law in which return is not necessarily threefold.
The ‘Rule of Three’ is sometimes described as karma by Wiccans, however this is not strictly accurate. Both concepts describe the process of cause and effect and often encourage the individual to act in a good way. However the concept of karma, according to the scriptures of Buddhism, Hinduism and other eastern belief systems, does not operate on a system of three-fold return. Furthermore, such belief systems do not contain the same concepts of ‘good’ and ‘evil’ that Wicca does.
According to John Coughlin the Law posits “a literal reward or punishment tied to one’s actions, particularly when it comes to working magic”. The law is not a universal article of faith among Wiccans, and “there are many Wiccans, experienced and new alike, who view the Law of Return as an over-elaboration on the Wiccan Rede.” Some Wiccans believe that it is a modern innovation based on Christian morality
Three-Fold Law, or Law of Return as it is also called, is perhaps one of the more controversial aspects of Wiccan ethics. The basic premise is that anything we do comes back to us in the end, often to a greater degree (such as three-fold). If we do good, then good will be retuned and if we cause harm, we put ourselves in danger of harm. Ethically it is equivalent to the Golden Rule: “Do unto others as you would have done to you”. But in the case of the Law of Return, there is a literal reward or punishment tied to one’s actions, particularly when it comes to working magic.
The debate over the validity of the Law of Return and its variations takes many forms. Some feel that it was created to keep new initiates in check as they learned to work with magic, while others feel it is a remnant of Christian thinking, being that a majority of Wiccans come from a Christian background. However, many Wiccans today, including some authors and “community leaders”, take the three-fold law quite literally.
Since the idea that “we reap what we sow” is generally accepted among Wiccans, the Law of Return can fairly be considered a core belief. However, it must be acknowledged that it is neither a necessary nor a universally defining belief of the Craft. There are many Wiccans, experienced and new alike, who view the Law of Return as an over-elaboration on the Wiccan Rede, which recommends that we refrain from causing harm. A Wiccan would not wish to cause harm since he or she deems it wrong to do so, not out of fear of retribution.
Background and Origins of the Threefold LawThe Rule of Three, also called the Law of Threefold Return, is a caveat given to newly initiated witches in some magical traditions, primarily NeoWiccan ones. The purpose is a cautionary one. It keeps people who have just discovered Wicca from thinking they have Magical Super Powers. It also, if heeded, keeps folks from performing negative magic without putting some serious thought into the consequences.
An early incarnation of the Rule of Three appeared in Gerald Gardner’s novel, High Magic’s Aid, in the form of “Mark well, when thou receivest good, so equally art bound to return good threefold.” It later appeared as a poem published in a magazine back in 1975. Later this evolved into the notion among new witches that there is a spiritual law in effect that everything you do comes back to you. In theory, it’s not a bad concept — after all, if you surround yourself with good things, good things should come back to you. Filling your life with negativity will often bring similar unpleasantness into your life. However, does this really mean there’s a karmic law in effect? And why the number three — why not ten or five or 42?
It’s important to note that there are many Pagan traditions that do not adhere to this guideline at all.
Objections to the Law of Three
For a law to truly be a law, it must be universal — which means it needs to apply to everyone, all the time, in every situation. That means for the Threefold Law to really be a law, every single person who does bad things would always be punished, and all the good people in the world would have nothing but success and happiness — and that doesn’t just mean in magical terms, but in all non-magical ones as well. We all can see that this is not necessarily the case. In fact, under this logic, every jerk who cuts you off in traffic would have nasty car-related retribution coming his way three times a day, but that just doesn’t happen.
Not only that, there are countless numbers of Pagans who freely admit to having performed harmful or manipulative magic, and never having anything bad coming back upon them as a result. In some magical traditions, hexing and cursing is considered as routine as healing and protecting — and yet members of those trads don’t seem to receive negativity back upon them every single time.
According to Wiccan author Gerina Dunwich, if you look at the Law of Three from a scientific perspective it is not a law at all, because it is inconsistent with the laws of physics.
Why the Law of Three is Practical
No one likes the idea of Pagans and Wiccans running around flinging curses and hexes willy-nilly, so the Law of Three is actually quite effective in making people stop and think before they act. Quite simply, it’s the concept of cause and effect. When crafting a spell, any competent Wiccan or Pagan is going to stop and think about the end results of the working. If the possible ramifications of one’s actions will likely be negative, that may make us stop to say, “Hey, maybe I better rethink this a bit.”
Although the Law of Three sounds prohibitive, many Wiccans see it instead as a useful standard to live by. It allows one to set boundaries for oneself by saying, “Am I prepared to accept the consequences — be they good or bad — for my deeds, both magical and mundane?”