The work of Guarino Guarini (1624-1683), theatine priest, mathematician, and architect, is examined as a case study of how the sacred was performed through practices of representation. Indeed, it is possible to focus on geometry and mathematical writings to argue that geometrical representation functioned as a performative practice within early modern Catholic culture, shaping religious perception, behavior, and hierarchy through the disciplined formation of vision. Moreover, the paper aims to highlight that treating geometry is not a simple, neutral technical language, but rather a purely symbolic expression of divine rationality. The paper situates Guarini's representational methods within the educational and institutional contexts of the Theatine order and its engagement with courts, colleges, and ecclesiastical spaces. Geometrical procedures such as projection, section, and spatial construction are analyzed as repeatable, rule-bound acts through which divine order was rendered intelligible and internalized by trained subjects. In this sense, representation itself operated as a form of sacred performance: a cognitive and pedagogical enactment that mobilized communities of learners, established epistemic hierarchies, and regulated access to legitimate ways of "seeing" the divine. By framing Guarini's geometrical practice as a performative mediation between theology, education, and social order, the paper contributes to broader discussions on how the sacred was enacted in early modern Europe beyond liturgical or devotional settings, stressing the role of scientific and educational institutions in both mitigating and reproducing forms of social and epistemic inequality.