Cats seem to go on the principle that it never does any harm to ask for what you want.
It may seem a strange principle to enunciate as the very first requirement in a hospital that it should do the sick no harm.
The natural principle of war is to do the most harm to our enemy with the least harm to ourselves; and this of course is to be effected by stratagem.
Buddhism's cardinal ethical principle is to avoid causing harm.
Make a habit of two things: to help; or at least to do no harm.
Principle comes first; action thereafter.