In the system of Attitude of Appraisal Theory, Affect is the centre and can be transformed into Judgment and Appreciation in institutional discourse. This study, based on a small corpus comprised of 30 political speeches by Nelson Mandela, attempts to investigate metaphor use in political discourse. The results show that appreciations are used in metaphors for objective description and subjective response, and the value of judgments is used to determine the inclusion of certain behaviors and values into the community of practice. This study by combining Conceptual Metaphor and Appraisal Theory will provide insights for scholars in certain fields.