People are more impressed with our sincerity if we act on our beliefs than if we merely talk about them.
actions speak louder than words
What one does is more important than what one says, as in Politicians need to be reminded that actions speak louder than words. This statement, a proverb found in many languages, including ancient Greek, was first worded in precisely this way in English in Colonial Currency (1736). Also see all talk; do as I say, not as I do.