This chapter examines how institutional and scientific discourse legitimizes authority through grammatical strategies that conceal the speaker’s agency. Drawing on functional and pragmatic linguistics, the text analyzes how impersonal constructions, agentless passives, and deontic modal forms (e.g., “it is said,” “must be fulfilled”) simulate objectivity and inevitability. These linguistic mechanisms, rather than reinforcing neutrality, establish ideological legitimacy by removing subjectivity from the utterance. Through examples from legal, academic, and religious texts, the chapter shows how grammar functions as a tool of epistemic closure, determining not only what is said but what can be said. The study draws on works by Halliday (2004), Hyland (2002), and Ducrot (1984), offering a multidisciplinary approach to discourse, power, and authority. This chapter is part of the forthcoming book Grammars of Power: How Syntactic Structures Shape Authority, and is published with the DOI 10.5281/zenodo.15395918 under a CC BY 4.0 license.