Bending the Judgment of a Convert is like Bending Gd's judgment: Chagigah 5a
Removing one's self from a case, if one knows that he won't be able to be indifferent: Shabbat 119a
Bad judges cause punishment for all of the Jews: Shabbat 139a
The Destruction of the Temple was a result of bad judges: Shabbat 139a
When the dishonest judges disappear, the oppressive government officials will disappear, too: Shabbat 139a