Whatever an enemy can do to an enemy,
Or a rival to a rival,
A wrongly directed mind
Will do worse to you than that.
What mother or father cannot do,
Or any other kin,
A rightly directed mind
Will do better for you than that.
These are some of my favourite verses from the Dhammapada, though in their apparent simplicity they are particularly difficult to translate. (The original Pali is given below.)