The Wiccan rede; explained

A lot of people only know a simplified version of the Wiccan rede
“Abide the wiccan rede ye must, in perfect love and perfect trust. Eight words the Wiccan rede fulfill; an’ it harm none, do what ye will.”

 In other words it’s karma, but instead of waiting for karma, you are karma. If someone did you wrong you can act as karma and get them back for what they did, as long as it's fair. If you didn't get them back then you'd be breaking the rede.

 Here is the full Wiccan rede (or at least one version of it). Most people only remember the first and last line.