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.

362. I heard the second animal saying, signifies out of the inmost heaven from the Lord. This is evident from what was said above n. 353; for by the animals are meant cherubim, and "cherubim," in the highest sense, signify the Lord in relation to providence and guard that He be not approached except through the good of love; and in a relative sense, the inmost heaven (See above, n. 152, 277, 313, 322). "Cherubim" signify also the inmost heaven because this heaven is in the good of love to the Lord, and the Lord cannot be approached except through the heavens, and into the inmost or third heaven there is nothing admitted that does not savor of the good of that heaven. There were four animals or cherubim, because "four" signifies conjunction into one, and such is the conjunction with those who are there; for the Lord thus conjoins them by means of love to Him from Him. For this reason four were seen. From this also it is clear that the second animal here has a similar significance as the first, and similar as the third and fourth in what follows. (That "four" signifies conjunction, see Arcana Coelestia 1686, 8877, 9601, 9674)