振振有词

to speak forcefully and with justice (idiom); to argue with the courage of one's convictions; also written 振振有詞|振振有词

(idiom) to speak forcibly out of a sense of righteousness

in the right and self-confident (idiom); bold and confident with justice on one's side; to have the courage of one's convictions

to twist words and force logic (idiom); sophistry

to contend on strong grounds; to argue strongly for what is right

to speak out for justice (idiom); to take a stand on a matter of principle