Equivalence between words of two languages is one of the topics that play an important role in translating and conveying the meaning desired by the author to the audience; In this method, the word in the source text is identified and the equation used in the target text is specified. This research tried to identify, extract and categorize the strategy and morphological and syntactic tools that are used in the text of Nahj al-Balagheh by descriptive-analytical method and can be equivalent to the conjunction "although" in Persian. Defining the format and syntactic construction, describing the issues that those letters were responsible for conveying, and stating the intentions of using those letters and the role responsible for the concept, however, are among the most important goals that the authors of the present article seek to achieve. One of the most important results of the present study is: some letters, although they do not have an independent meaning in appearance, play a key role in inducing the intended meaning of the speaker. The equations "although" in Persian are not limited to the two letters "lu" and "an" in Arabic, but based on the text of Nahj al-Balagheh and considering the context the text, other letters such as but, except , Inflection letter, syntactic role of present tense and adjective can be a suitable and practical equivalent for the conjunction letter, although in Persian. Some purposes were used only in a particular style and others had a common purpose. By studying the extracted samples, it was found that the purpose of "perception" has the highest frequency among rhetorical purposes and has been used in almost all structures and is more compatible with the meaning of the letter "although".