The conciseness of the Qur'anic language is matchless. As Allah's word in the Qur'an befit being kept by hearts, they require concise and precious words and expressions that are rich in meaning despite concision. The Principle of Least Effort has several categories one of which occurs in the paradigmatic axis, where a brief and contentful linguistic structure replaces a long one. This article, with its descriptive and analytic method, aimed at studying some manifestations of the Principle of Least Effort in the category of substitution at phonetic, lexical, syntactic, and rhetorical levels. It is assumed that the Qur'an's readership, from the illiterate to modern readers need speech that can be memorized because languages are heading rapidly towards simplification. Therefore, Allah's speech in the Qur'an created phonetic harmony and attempted at word selection in a way that observes balance and that each generation of readers can utilize and commit them to their hearts.