In Luke 12:51, 53: By father against son, and by son against the father, is understood evil against truth, and truth against evil; and by mother against daughter, and by the daughter against the mother, is understood the lust of falsity against the affection of truth, and vice versa. (Apocalypse Explained 504[31])

(Odkazy: Apocalypse Explained 504)

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.