E3P40C2
Corollary — Part III
Latin
Si aliquis imaginatur ab aliquo quem antea nullo affectu prosecutus est, malum aliquod præ odio sibi illatum esse, statim idem malum eidem referre conabitur.
English (Elwes 1883)
If a man conceives that one, whom he has hitherto regarded without emotion, has done him any injury from motives of hatred, he will forthwith seek to repay the injury in kind.
Modern English
If someone imagines that another person toward whom he previously felt no affect has done him some harm out of hatred, he will immediately strive to repay that same harm to that person.