Speak no untruth,
Do none harm,
Treat all with respect.
Beyond these do according to your will.
The above words which are called The Law is the first lesson taught within The Path of Light. It is taught first to people coming to the craft to provide limits and ethics ensuring a healthy learning process providing growth and spiritual progress.
Often worded differently these tenets are held dear to many spiritual paths. Essentially meaning to live honestly, speak with honesty, endeavor to be polite, and try not to hurt others. After you have taken all that into consideration you may act upon your will. Being honest does not mean you have to tell the world everything, it simply means to be honest word and deed.
The tenet on not causing harm to anyone also includes not doing harm to yourself. The charge to do no harm is an obligation to reasonably take action to make sure those around us do not come to harm nor cause harm. We have the responsibility to think and make a conscious assessment of all the consequences of our actions or inactions.
Respect is the key to it all. Without respect for others, for yourself, there is no chance of even managing the other tenets. Don't be thoughtless and rude. Behaving offensively is disrespectful not only of the one it's directed at it's disrespectful of all that come within range. It is necessary to think about what we do and say and take responsibility for our actions.
Magic is an act of will, the exercise of will is what is done after the other avenues are exhausted. This tenet lays the foundation for being very cautious in the exercising of will and its magical end product.