The sermon of Fadak is one of the most important traditional heritage of Fátima Al-Zahra, the daughter of the prophet of Islam (p.b.u.h.) which has been delivered after the demise of the prophet at al-Masjid al-Nabi and as an eloquent prose, enjoys eloquence, firmness of style and agreement among the components. In this research, efforts have been made to study the elements of grammatical cohesion of the text at The Sermon of Fadak based on the functional role of Halliday and Hasan. The research methodology is descriptive-analytic and the research population is textual, including The Sermon of Fadak of Hazrat Zahra(S) in the book of Al-Ehtejaj Al Ahl-el Lejaj by Tabarsi. « الاحتجاج ع لی اهل ال ل جاج » The findings of the research showed that in The Sermon of Fadak, the factors of grammatical cohesion include ellipsis, substitution, reference, and inflection. The application of the factors of grammatical cohesion at The Sermon of Fadak, in addition to creation of cohesion at the text level has caused the increase of impact on addressees and has increased the beauty of the text. Though some of the factors of grammatical cohesion in The Sermon of Fadak are in agreement with the model of Halliday but the efficiency of this model is not in agreement with that in some cases such as the verb substitution at The Sermon of Fadak as an eloquent Arabic literature prose.