An instance from the life of President Abraham Lincoln.
When he was practising as a lawyer, a client approached him and told him about his case in detail. After studying the case, Lincoln returned the file to the client. The client wanted to know why he was returning the file. He wanted Lincoln to accept his case. But Lincoln said, "May be I can win this case on some point of law, but it is a false case in point of fact. When I stand up in the court to speak, my conscience would reproach me, You're telling a lie, Lincoln!', it would say. It might even impel me to admit that the case was false!"
Source: © Facebook