Does Islamic Law Deal With Minimum Wage?

There is a fundamental problem when I read this paper titled: Islamic Commercial Law and Social Justice: Shari'ah Compliant Companies, Worker's Rights and the Living Wage (written by Susan C. Hascall), namely, the fact that she argues that some of the Prophet's Hadiths can be used to support the existence of minimum wage for employees and the notion that a company cannot claim itself to be Shari'a compliant without complying with minimum wage requirement. Why? Let us read first the Hadiths used by Ms. Hascall below: " Give a servant his fee before his sweat dries " " God Most High said: I shall be the opponent of three people on the day of judgment: the man to whom I gave generously but then he cheated; the man the man who sold a freeman into slavery and ate up its price, and the man who hired a worker and took his due measure from him but did not pay him for his (fair) wages " The word "fair" that I underline above is an additio