Don’t bite the hand that feeds you

 Meaning Don’t harm, criticize, or betray the person or group that supports or helps you.

In other words — don’t turn against those who give you benefits, care, or opportunities.

• He insulted his boss online — clearly biting the hand that feeds him.
• You shouldn’t speak badly about your parents; don’t bite the hand that feeds you.

Origin:

It comes from the idea of an animal biting the hand of the person feeding it — an act of ingratitude or foolishness.