It is a trait of the man of sense to derive profit even from his enemies. - Plutarch

Know how to listen, and you will profit even from those who talk badly.

It was not said amiss by Antisthenes, when people told him that one Ismenias was an excellent piper, “It may be so,” said he, “but he is but a wretched human being, otherwise he would not have been an excellent piper.” And king Philip, to the same purpose, told his son Alexander, who once at a merry-meeting played a piece of music charmingly and skilfully, “Are you not ashamed, son, to play so well?” For it is enough for a king or prince to find leisure sometimes to hear others sing, and he does the muses quite honor enough when he pleases to be but present, while others engage in such exercises and trials of skill. He who busies himself in mean occupations produces, in the very pains he takes about things of little or no use, an evidence against himself of his negligence and indisposition to what is really good.

It is part of a good man to do great and noble deeds, though he risk everything.