May Allah protect us! It is a directed saying, its apparent meaning is that it is obligatory regarding your fatwa to take the one who found the goods in his luggage and enslave him. If we took someone else, that would be injustice in your view. So why do you seek what you know to be unjust? Its inner meaning is that Allah commanded me and revealed to me to take Benjamin and detain him for a benefit or for many benefits that He knows in that. If I took someone other than the one He commanded me to take, I would be unjust and acting contrary to the revelation. The meaning of 'May Allah protect us' is that we seek refuge in Allah from taking. Thus, the source is added to the object and 'from' is omitted. And 'if so' is an answer for them and a recompense, as for their saying, 'So take one of us in his place.' The meaning is that if we took his substitute, we would be unjust.