Almost every religion has their Creeds - a set of fundamental beliefs or ideology - that they follow. Most of them say "this is the one true way" or that "you have to believe this way or else!" but Wicca isn't like that. We have the Witches' Creed, the Charge of the Goddess and Charge of the God, and in Greek Wicca we have Charges - or explanations of faith and practices - from each of the many Gods and Goddesses of the Greek Pantheon.
It is not our way to have commandments and orders to follow some one and only true path - it is our way to find a balanced and peaceful path for us without pushing it on anyone else - that is proselytization....not our way.
We do, however, have one All encompassing rule - called the Wiccan Rede. A rede (pronounced reed OR rahday) is advice or counsel given by one person to another. In this case, it is the advise given to us by the creators of Wicca.....but as it matches up with most Laws of Reciprocity in about every religion - I believe it comes to us from the Divine. It is one of those common core beliefs held in human nature, that civilizes us and joins us together against our base survival instincts. Here is a wikipedia link to the Wiccan Rede, you should read it so that you know the history behind it. An Ye Harm None, Do As Ye Will.