The term 'بیع' [sale] and its derivatives are mentioned more than 20 times in Nahj al-Balaghah. Imam Ali (PBUH) used the word to convey his divine message regarding the regulation of the relations between humans and God, who is the center of the world. In terms of jurisprudence and law, بیع is generally interpreted as the exchange of property, i.e., it implies both purchasing and selling. On the other hand, the term has a customary meaning and is regarded a signed order. This paper discusses the word بیع and the worldview governing it in Nahj al-Balagha. While examining the term as used in the words of Ali (PBUH), the study determined its  meaning by analyzing its definition in the civil law and other jurisprudential and legal contexts. The findings show that the term has been used in Nahj al-Balagheh in its common and customary sense, i.e., exchange. Also, through a descriptive analytical method, it became clear that the purpose of using this term in Nahj al-Balagheh was only to express this fact that humans are always trading and exchanging with God, as the center of the world; in every step they take, they are trading and exchanging in some way. Pious people carry out profitable transactions and business. However, in this business some people suffer loss due to negligence and not observing the God's rights and people's rights.