“First do no harm!”
“The first rule of being a ninja is, 'Do no harm.' Unless you mean to do harm. Then do lots of harm.”
“Primum non nocerum. (First do no harm)”
“The very first requirement in a hospital is that it should do the sick no harm.”
“A single thought, he considered, could do all sorts of harm. Harm to what, he wasn't sure, but he identified it as harm.”
“He could not harm me, for I do not think it is permitted that a better man be harmed by a worse”