Русско-английский словарь пословиц и поговорок
ЧЕЛОВЕК САМ СЕБЕ НЕ СУДЬЯ
No man can be unbiased enough in his own case to give a just estimation of his own doings
Var.:В своём деле никто сам себе не судья
Cf:Не who will have no judge but himself condemns himself (Br.). If you judge your own case, you are judged by a fool (Am.). Men are blind in their own cause (Am.,Br.). No man ought to be judge in his own case (Br.)