The linguistic rule “increase in form indicates increase in meaning” is a well-known principle linking morphological structure to semantic depth. This rule occupies a prominent place in works of morphology, rhetoric, and Qur’anic exegesis; however, its validity and universality have long been debated among linguists due to the subtle semantic distinctions between verbal and nominal patterns in Arabic. This study adopts a descriptive–analytical methodology, examining occurrences of the rule across classical linguistic and exegetical literature, analyzing morphological and rhetorical evidence, balancing the arguments of proponents and opponents, and testing the alleged counterexamples by applying the recognized linguistic conditions for the rule’s applicability. The study aims to evaluate the rule’s validity and limits, define the conditions governing its application by distinguishing between semantic increase and purely functional morphological changes, identify the degree of generality with which the rule operates, and assess its explanatory value in rhetoric and Qur’anic interpretation. The findings confirm that the rule is fundamentally valid, yet not absolute: it applies only where form, derivation, and morphological category are unified, and does not apply to functional or stylistic increases in form. Ultimately, the research concludes that the rule is predominantly reliable, operating within a clearly defined framework; and adhering to its conditions leads to a more precise understanding of Arabic patterns and their semantic implications, making it a valuable analytical tool in linguistic and rhetorical studies.