bite the hand that feeds you
US /baɪt ðə hænd ðæt fiːdz ju/
UK /baɪt ðə hænd ðæt fiːdz ju/
1.
to harm someone who is helping you or providing for you
:
•
He shouldn't bite the hand that feeds him by criticizing his boss publicly.
•
After all the help they gave him, it was shocking to see him bite the hand that feeds him.