Abu Al-Qasim Umar ibn Thabit Ibn Ibrahim ibn Umar ibn Abdullah Al-Octani (d. .442 A.H.), was one of the imams of Arabia, and he was a scholar of grammar, and well-versed in its rules, with numerous authored works. Among his writings is "Al-Fawa'id and-Al-Qawa'id" (The Benefits and Rules), in which he adopted a clear and straightforward approach in his examples, illustrations, and rules, avoiding obscure terms and complex styles. The aim of this study is to understand the extent of al-Thamanini's attention to Quranic citations in his book "Al-Fawa'id wal-Qawa'id," his use of most surahs, his concern with the term "citation," his restriction to Quranic citations in some grammatical topics, and his preference for Quranic citations over other sources in grammatical issues. The study also looks into how he selects citations that align with grammatical rules, addresses the various rare and weak readings, favors the most suitable and eloquent readings, and expresses his opinions on them. It examines the impact of these citations on establishing and formulating grammatical rules. All of this is to highlight the significant influence of the Holy Quran in establishing grammatical rules, which helps set correct and sound standards for Arabic grammar by relying on numerous Quranic citations. The aim is to present grammatical material in a smooth manner that benefits the learner. Keywords : Impact, Al-Thamanini, Witness, Norm, Readings