“The Wiccan Rede” is a poem, usually summed up in a couplet Eight words the Wiccan Rede fulfill, An it harm none do what ye will first publicly spoken by Doreen Valiente in 1964. It makes up the basic ethical code of the various branches of Wicca that adhere to it, though it is considered advice, not commandments. There are several versions of the Wiccan Rede and of these interpretations may vary between covens.
In 1974 a 26-line version appeared in Earth Religion News. That version (I believe) can be found at https://sites.google.com/site/foxvalleyappletonpaganpride/wiccan-rede
Another version was published in The Green Egg by Lady Gwen Thompson. She attributed this version to her grandmother Adriana Porter. The full text can be found at http://thewicca.ca/people/nova-scotia/adriana-porter.php
These versions are often referred to as “the long rede”. I cannot find conclusive evidence that the “short rede”, that is An it harm none, do what ye will was ever articulated, at least with this wording, prior to the scribing of Doreen Valiente’s 1964 speech, but the idea was certainly there. In The Meaning of Witchcraft, Gerald Gardner mentions that “(Witches) are inclined to the morality of the legendary Good King Pausol1, “Do what you like so long as you harm no one”.