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

Whatever an enemy might do to an enemy,
or a foe to a foe,
the ill-directed mind
can do to you even worse.

Udāna 4.33
Translated from the Pali by Thanissaro Bhikkhu