5586. 'Unless your brother is with you' means unless the intermediary is with you. This is clear from the representation of 'Benjamin' as the intermediary, dealt with in 5411, 5413, 5443. The intermediary represented by 'Benjamin' serves as the link between the internal and the external, that is, between the spiritual man and the natural man; also, it is the truth of good that goes forth from truth from the Divine, represented by 'Joseph'. This truth of good is called the spiritual of the celestial - 'Benjamin' being the spiritual of the celestial, see 3969, 4592. A person's internal and external are completely distinct and separate from each other; for his internal dwells in the light of heaven, his external in the light of the world. And being completely distinct and separate they cannot be joined together except through the intermediary which derives its existence from both of them.

Fire, in the spiritual sense, can mean either love or hatred depending on the context, just as natural fire can be either comforting in keeping you warm, or scary in burning down your house. Our language reflects this, too -- we use concepts like a smoldering hatred or a burning love. So fire signifies a love, either a good love of the neighbor and to the Lord, or, in a bad sense, selfish love of oneself that, if unchecked by conscience, leads to hatred of anyone that opposes it.