Wicca
There is a rule in Wiccan (branched from Pagan belief) that is called "the rule of threefold return" or "the threefold rule" or "the rule of three", or called equivalent names that use the word "law" instead of "rule". The rule of threefold return is a belief that what you do for good or bad will return to you 3 times the original intent. Therefore, you should only send out or work with good intentions to avoid three-times the bad return as Karma. The rule of threefold return is revealed to second-degree initiates (though they are usually already familiar with it) during the second-degree initiation ritual, in which the initiator scourges the initiate, and then the initiate returns three times the number of scourgings to the initiator. That second-degree initiation ritual, along with the threefold rule within it, were made public by Gerald Gardner's 1949 book High Magic's Aid, in chapter 17.