be fair!

be fair

A call to treat someone fairly and sensibly. Oh, be fair—let your brother ride in the front seat for a change.
See also: fair
Farlex Dictionary of Idioms.

ˌbe ˈfair!

(spoken) used to tell somebody to be reasonable in their judgement of somebody/something: Be fair! She didn’t even know you were coming today.
Farlex Partner Idioms Dictionary
See also:
  • be fair
  • for fair
  • fair and square
  • bid fair
  • make fair weather
  • with (one's) own fair hands
  • fair up
  • faired
  • fairing
  • fair off