Two brothers were playing. The younger brother got angry because the older brother took his toy. It caused a fight. Of course, it is not right for the younger one to hit the older one, but the older brother also did something wrong. The older one was usually well-behaved, while the younger had often caused trouble and given his parents a hard time. If the mother heard from the older one that his brother had hit him first, by her bias toward the elder she'd scold the younger. Then, the younger would feel he was treated unfairly. To avoid bias we must listen to both sides impartially. Only then can we discern more accurately what is right.