This study examines the prose style of Ishaq Shirazi Nayrizi in a fraternal letter addressed to Prince Tahmasp Mirza Mu’ayyid al-Dawla on the occasion of a festive celebration. The selection of this letter as the subject of analysis stems from the scarcity of studies exploring the literary contributions of this writer, particularly in terms of stylistic and intellectual content analysis. The research pursues two primary objectives: first, to identify the key themes and ideas conveyed in the letter; and second, to explore the literary and rhetorical style employed by the author to express these themes. To achieve these objectives, the study adopts a stylistic approach, utilizing a series of analytical steps that focus on three core elements: linguistic, functional, and literary. The findings reveal that the letter’s primary themes include expressions of profound appreciation and respect for the addressee, complaints about hardships, and expressions of hope and prayers for improved circumstances and optimism for the future. The author employs a refined literary and rhetorical style, characterized by linguistic balance and expressive precision to convey the intended meanings. This is evident in the letter’s meticulous structure, the use of figurative imagery, rhetorical embellishments, and subtle allusions to a political stance. In summary, the study highlights the author’s mastery in harnessing language and rhetorical techniques to serve meaning, while also underscoring his persona as a skilled litterateur who balances genuine emotion with stylistic distinction.