The signification of the word "expression" in the verse "Knowledge of expression" on human speech and speaking and its consequences from the Qur'an's point of view using religions interpretations

Some commentators consider "expression" in meaning of the power of speech, some have suggested it as the expression of everything, the names of objects and creatures, and others have introduced it as the power of reason, and some have meant it as Holy Qur'an. Given the differences in the meaning of expression and lack of independent research in this regard, this article tries to analyze the correct meaning of "expression" in this verse. the opinion of those who consider "expression" in the meaning of speech seems correct. Because first meaning of expression that comes to mind in the context of the verses of first al-Rahman is speech. There is evidence in earlier literary, historical and narrative texts that expression is used in the meaning of speech. Also in the fourth verse of Ibrahim, explanation is attributed to language. On the other hand, Almighty God calls Qur'an an expression for the people, and since the nature of Qur'an at the time of revelation was nothing but the nature of speech and language, it becomes clear that the meaning of expression is speaking. On the other hand, the other meanings mentioned by commentators for expression are somehow related to language and speech.