I am looking for a proverb describing not to stoop oneself to another person's "level".
A similar proverb is
"If you lie down with a dog, you'll get up with fleas"
but this is not exactly what I have in mind as according to wikipedia, this proverb appears to focus more on choosing "your company" well (to be associated with), which hinges on the connotation that dogs are human's best friends.
According to wikipedia
The quote has a large almost universally agreed meaning of "You should be cautious of the company you keep. Associating with those of low reputation may not only lower your own but also lead you astray by the faulty assumptions, premises and data of the unscrupulous (https://en.wikipedia.org/wiki/Wikipedia:If_you_lie_down_with_dogs,_you_get_up_with_fleas)
The proverb(s) I am looking for would portray the others (with a presumptive lower level of standard) more as enemies, not as friends