bite the hand that feeds you

字面上的意思是不要咬给你喂吃的东西的手，当别人好心照顾你，甚至亲手把饭喂到你嘴里，而你却把那只手给咬了，这不就是在恩将仇报嘛。

to hurt someone who helps you; to go against the person or thing that provides something necessary

伤害帮助你的人;反对给你提供必要东西的人或物

The college gave me a scholarship, so I shouldn't bite the hand that feeds me and criticize its hiring policies .

学校给了我奖学金，所以我不应该恩将仇报，批评学校的招聘政策