Sayyidna Jareer ibn Abdullah, Radi-Allahu anhu, once sent his servant for buying a horse. The servant made a deal for three hundred dirhams and brought the seller with him so he could be paid. Sayyidna Jareer ibn Abdullah, Radi-Allahu anhu, looked at the horse and realized that the seller had undervalued it. "Would you sell it for four hundred?" he asked. The seller agreed. "How about five hundred?" he continued his unusual "bargaining" and finally bought the horse for eight hundred dirhams. He was later asked why he did so. "The seller was not aware of the true value of this horse, " he explained. "I have simply given him a fair price because I had promised to Prophet Muhammad, Sall-Allahu alayhi wa sallam, to always be sincere and well-wisher for every Muslim."
Ibn Al-Qayyim, may Allah have mercy on him, said, “Indeed, the Shariah is founded upon wisdom and welfare for the servants in this life and the afterlife. In its entirety it is justice, mercy, benefit, and wisdom. Every matter which abandons justice for tyranny, mercy for cruelty, benefit for corruption, and wisdom for foolishness is not a part of the Sharia even if it was introduced therein by an interpretation.” (Source: I’lām al-Muwaqqi’īn 3/11)