Verbal mood is one of the fundamental categories of Persian grammar, playing a pivotal role in conveying the speaker's attitude toward a proposition. In mystical texts, particularly in expressing didactic and spiritual concepts, its function becomes even more pronounced. Attar Neishaburi's masterpiece, Mantiq al-Tayr, as one of the most prominent mystical works in Persian literature, provides an ideal framework for examining modal functions, specifically the subjunctive mood. This study aims to elucidate the semantic and rhetorical functions of the subjunctive mood and analyze its position in contrast with other grammatical moods across the seven valleys of this work. Employing a descriptive-analytical approach, the research encompasses the entire corpus of the seven valleys, utilizing a census method combined with qualitative content analysis and grammatical coding. The results indicate a high frequency of the subjunctive mood, employed to express concepts such as spiritual imperatives, desire, possibility, doubt, and semantic suspension. Furthermore, the analysis of frequency distribution reveals that the subjunctive mood follows a descending trajectory, shifting from a prescriptive and mandatory function toward a descriptive and potential one. This structural transition precisely aligns with the stages of the spiritual journey and the seeker's transition from multiplicity to unity. Consequently, it can be concluded that Attar consciously leveraged the capacities of the subjunctive mood to enhance the semantic and pedagogical layers of his work, making verbal mood an essential tool in conveying the mystical experience and embodying the path of annihilation (*fana*) within this poem.