be (not) (one's) brother's keeper

be (not) (one's) brother's keeper

To be responsible for the actions, behavior, or whereabouts of one's close relative or friend (not necessarily a brother). Often used in the negative to express frustration that such responsibility is assumed. Of course I'm disappointed that Travis got arrested again, but I'm not my brother's keeper. When I'm babysitting him, I'm my brother's keeper.

See also: keeper

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

be one's brother's keeper

to be responsible for someone else. (Used of others besides just real brothers.) I can't force these kids to go to school and get an education so they can get jobs. I am not my brother's keeper. You can't expect me to be my brother's keeper. Each of us should be responsible for himself! be one's own man and be one's own master to be someone who is not controlled by other people; to be an independent person. Bert longed to be his own master, but at the same time feared losing the security he had as the employee of a large company. When I go away to college, I'll be my own man. My parents won't be able to tell me what to do anymore.

See also: keeper

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.