The qualities of a good prosecutor are as elusive and as impossible to define as those which mark a gentleman. And those who need to be told would not understand it anyway. A sensitiveness to fair play and sportsmanship is perhaps the best protection against the abuse of power, and the citizen’s safety lies in the prosecutor who tempers zeal with human kindness, who seeks truth and not victims, who serves the law and not factional purposes, and who approaches his task with humility.

Robert H. Jackson (1892-1954) US Supreme Court Justice (1941-54), lawyer, jurist, politician
“The Federal Prosecutor,” speech, Conference of United States Attorneys, Washington, DC (1940-04-01)
    (Source)

Concluding words. Delivered while Jackson was the US Attorney General. Reprinted in the Journal of the American Judicature Society (1940-06).