Gratitude is the memory of the heart.

The saying frames gratitude not as a fleeting feeling but as a durable faculty of remembrance: the “heart” retains benefits received and, by remembering them, sustains thankfulness over time. It implies that ingratitude is less a lack of manners than a failure (or refusal) to remember—an ethical lapse rooted in forgetfulness. The metaphor also suggests that gratitude is relational and cumulative: the heart’s memory stores kindnesses, shaping character and guiding future reciprocity. As an aphorism, it compresses a moral psychology—emotion, ethics, and recollection—into a single image, which helps explain its long afterlife in moral instruction and commonplace books.