Qatadah (may Allah have mercy on him) said: When two mukatabs buy each other, this one from his owner and that one from his owner, then (in such a case) the sale of the one who bought first will be considered valid (and the sale of the other will be void), and the people of Madinah say that the right of wala’ (inheritance) will belong to the selling owner. They say: The one who bought has purchased that which was obligatory upon the mukatab to pay, therefore the wala’ will belong to the owner.