Dhammapada 42

42

Diso disaṃ yaṃ taṃ kayirā,
verī vā pana verinaṃ;
Micchāpaṇihitaṃ cittaṃ,
pāpiyo naṃ tato kare.

Whatever a hater may do to a hater, or
[40. Anivesana has no doubt a technical meaning, and may signify, one who has left his house, his family and friends, to become a monk. A monk shall not return to his home, but travel about; he shall be anivesana, 'homeless,' anâgâra, 'houseless.' But I doubt whether this can be the meaning of anivesana here, as the sentence, let him be an anchorite, would come in too abruptly. I translate it therefore in a more general sense, let him not return or turn away from the battle, let him watch Mâra, even after he is vanquished, let him keep up a constant fight against the adversary, without being attached to anything or anybody.] an enemy to an enemy, a wrongly-directed mind will do us greater mischief.