As we express our gratitude, we must never forget that the highest appreciation is not to utter words but to live by them.

Kennedy contrasts verbal gratitude with enacted gratitude. The line argues that appreciation reaches its “highest” form only when it becomes conduct—when thanks is translated into loyalty, service, or ethical action consistent with what one praises. Implicitly, it critiques ceremonial or performative expressions of thanks (speeches, proclamations, polite formulas) that are not matched by behavior. In a civic register often associated with Kennedy, the thought also fits a public-morality ideal: citizens and leaders honor sacrifices and ideals not by repeating them, but by living up to them in policy and daily life. The quote’s enduring appeal lies in its simple test of sincerity: actions authenticate words.