If you say: What does this refer to? I say: It has been imagined as a separation between them when its time arrives, as Musa, peace be upon him, said: If you ask me about anything after this, do not accompany me. So he pointed to it and made it a subject and informed about it, just as you say: This is your brother. Thus, 'this' cannot refer to anyone other than the brother. It may also refer to the third question, meaning: This objection is the cause of the separation. The original is: This is a separation between me and you. Ibn Abi Abla has read it this way, so the source is added to the circumstance just as it is added to the object.