Do no harm

"Oh, make your mind easy! I shall do no harm, if I do no good."

[G]et government out of the gambling business. . . . These officials pervert public policy, which should at least do no harm.

First, consider the moral minimum, do no harm.

A doctor's principle code is, "First, do no harm."

Hence, some people consider non-maleficence to be the most basic of all the cardinal principles of ethics; it lays down the least minimum condition for ethical correctness, as if to say: "even if you would not do good, at least do no harm."