理直气壮

to speak forcefully and with justice (idiom); to argue with the courage of one's convictions

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

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

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

devotion to righteousness that inspires reverence (idiom)