You should be a monster.
Philosopher Francois de La Rochefoucauld:
“Nobody deserves to be praised for goodness unless he is strong enough to be bad, for any other goodness is usually merely inertia or lack of will-power.”
Psychologist Jordan B. Peterson:
"You should be a monster. An absolute monster. And then you should learn how to control it."
Bible, Genesis 4:7:
"...And if you do not do well, sin is lurking at the door; and its desire is for you, but you must master it."