Whoever battles with monsters had better see that it does not turn him into a monster. And if you gaze long into an abyss, the abyss will gaze back into you.

Battle not with monsters lest ye become a monster and if you gaze into the abyss the abyss gazes into you.

Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.

Whoever fights monsters should see to it that in the process he doesn't become a monster

Battle not with monsters lest you become one.

He who fights too long against dragons becomes a dragon himself; and if you gaze too long into the abyss, the abyss will gaze into you.