In Genesis 19:24, it appears in the sense of the letter, as if there were two Jehovahs: one on earth, and one in heaven. When Jehovah is first named it refers to the Lord's divine human, and the second time the essential divine or the father.

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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.