This text presents a critical re-examination of the traditional philosophical principle "operari sequitur esse" (activity follows being). The author argues that the universal validity of this principle is questionable, as there is no "esse" without activity; being must be performed and cannot precede its own execution. The reflection focuses on the relationship between an event, its self-performance, and the establishment of a subject. It distinguishes between the being of the event itself and the being of the subject constituted by that event. If "operari" is understood as the performance of something beyond mere existence—an activity that results in a "work" (ergon) affecting the environment—it must be the performance of a subject already established by the event. Consequently, the concept of "esse" requires redefinition to account for the distinction between the internal self-performance of an event and its active self-transcendence toward the exterior. This analysis offers a deeper insight into the ontology of activity and the procedural nature of subjectivity, emphasizing the dynamic interconnection between being and its manifestation.