This thesis examines the linguistic performativity of koan literature in Zen Buddhism and Meister Eckhart's use of "Grunt" in his sermons. It argues that koans and Eckhart's language aim not to communicate ideas but to induce spiritual transformation through dialectical engagement with paradoxical statements. The thesis draws on Pierre Hadot's view of ancient philosophy as "spiritual exercises" that formed character through practices rather than imparting knowledge. It aims to show koans and Eckhart's language functioned similarly, disrupting habitual thought and guiding readers toward conversion through confrontational dialogues that question conventional understanding.