He delighted to advocate the cases of those whom he knew to be wronged, but he would not defend the cause of the guilty.  If he discovered in the course of a trial that he was on the wrong side, he lost all interest, and ceased to make any exertion.
 
Once, while engaged in a prosecution, he discovered that his client's cause was not a good one, and he refused to make the plea.  His associate, who was less scrupulous, made the plea and obtained a decision in their favor.  The fee was nine hundred dollars, half of which was tendered to Mr. Lincoln, but he refused to accept a single cent of it.
 
His honesty was strongly illustrated by the way he kept his accounts with his law-partner.  When he had taken a fee in the latter's absence, he put one half of it into his own pocket, and laid the other half carefully away, labeling it ``Billy,'' the name by which he familiarly addressed his partner.  When asked why he did not make a record of the amount and, for the time being, use the whole, Mr. Lincoln answered:  ``Because I promised my mother never to use money belonging to another person.''