“I once asked abu Ja‘far (a.s.), about the case of a man who buys a slave from another man who had two slaves and he says to the buyer, Take both of them then choose whichever you like and return the other’ and he has received payment. The buyer takes both of them but one of them runs away from the location of the buyer. He (the Imam) said, ‘He must return the one with him and take half of the price he has paid, then search for the runaway slave. If he finds him he then chooses either one that he likes and returns the other. If he does not find him the slave belongs to both of them in the manner of equal shares.’”