and fasting and Hajj.

Whatever has no definition in either language or revealed law is referred to people’s customary usage, as with taking possession, mentioned in the Prophet’s saying (may Allah bless him and grant him peace):

“Whoever buys food must not sell it until he takes possession of it.”

It is well known that the Lawgiver has laid down no definition for sale, hire, gift and the like, either in Allah’s Book or in the Sunnah of His Messenger. Nor has it been reported from any of the Companions or Successors that he prescribed a particular form of words or other conduct for contracts, or said anything indicating that contracts are concluded only through specific formulas. Indeed, it has even been said that this view contradicts the early consensus and is an innovation.

Nor is there a definition in the Arabic language by which one could say that its speakers call one transaction a sale but do not call another a sale, so that one falls within the scope of Allah’s address while the other does not. Rather, the fact that Arabs customarily call these contractual dealings sales is evidence that they are called sales in their language. The presumption is that established linguistic usage is retained and upheld, not displaced or altered. Thus, when something has no definition in revealed law or language, reference must be made to people’s customary usage and practices. Whatever they call a sale is a sale, and whatever they call a gift is a gift.

The third point:

People’s words and deeds are of two kinds: acts of worship through which their religious life is set right, and customary practices which they need in their worldly lives. By surveying the principles of the revealed law, we know that the command to perform acts of worship which Allah has made obligatory or loves can be established only through revealed law. As for customary practices, these are what people habitually do in their worldly lives, involving matters that