Textual coherence has long been of interest to linguists as one of the fundamental pillars of textual communication. The reason is that the coherence of the text and the recognition of its factors make it easier to understand the text. This strengthens the reader’s motive to read the text, creates a logical relationship between the events, and prevents textual misunderstanding in many cases. According to Halliday and Hassan (1976), omission is one of the instruments in textual coherence that creates the link between the reader and the text on the one hand and the reader’s conjecture and the notion of lexical omission on the other, thereby establishing the coherence of the text. It is essential to study the coherence in the Holy Quran linguistically as Quran has been revealed to the Holy Prophet (Peace Be Upon Him) gradually as a coherent and interconnected system from the Lord Almighty. Therefore, this article is an effort to study “omission” in the story of Prophet Moses in Surah Al-Qasas using an analytical and comparative method and then analyze its effect on the coherence of the verses of this Surah. One of the most important conclusions of this article is that omission leads to brevity and conciseness that accelerate the development of the story.