Speak the truth, even if your voice shakes.
Courage here is not the absence of fear but honesty that keeps going while the fear is plainly audible. The line separates two things we often fuse: feeling afraid and being silenced. A shaking voice doesn't make the truth any weaker. It is just what it costs a person to say something that matters. So don't wait to feel calm first, because that moment may never arrive.
The idea suits Maggie Kuhn, who was forced to retire at 65 and went on to help found the Gray Panthers. She challenged ageism and spoke out on peace and justice at an age when society expected her to be quiet. The wording is widely attributed to her, though I know of no firmly cited original source for it.
Today, someone might notice a colleague's idea being credited to another person again and again. Instead of rehearsing until they feel brave, they say in the next meeting, "I'd like to point out that was Priya's idea," dry-mouthed and unsteady. The tremor passes, while the silence might not have.