In the twentieth century, time became a key-concept for music – maybe the art more dependent on time. Even so, a myriad of definitions did turn this idea not only into a rich element for musical discourse but also into a conceptual battlefield in discourses about music. Unfortunately, there was an issue for this struggle between theoretical ideas and musical composition that always insisted in striking the debate: the performance. Thus, this is the aim of this short reflection: to bring performers as protagonists in the debate, listening to their experience in time and of time in performance. For this, the Augustinian link between Time and Memory is taken as a bottom line for the discussion. In understanding music as a kind of discourse, another important conceptual device will be claimed for this reflection, that is Rhetoric. The first part of this reflection recollects concepts from the Aristotelian and Augustinian approaches on time and discourse, and concludes with a review of the main definitions of time by composers in the twentieth century. The second part reviews three theoretical approaches of musical form as process. A third section comprises the embodiment of those discussions into practice in the Cello Sonata, written by Bernd Alois Zimmermann.