Wiccan Rede:
The Wiccan Rede, a foundational principle in Wicca, often includes the Law of Three. While the full Rede emphasizes 'An ye harm none, do what ye will,' the Law of Three adds the idea that even actions taken without harming others will have consequences that amplify three times.
Karmic Principle:
The Law of Three is often viewed as a karmic principle, suggesting that any energy released, whether positive or negative, will return to the original sender threefold.