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2 And lo, six men are coming from the way of the upper gate, that is facing the north, and each his slaughter-weapon in his hand, and one man in their midst is clothed with linen, and a scribe's inkhorn at his loins, and they come in, and stand near the brazen altar.
Bloods signify evil in Ezekiel 16:9.
(References: Arcana Coelestia 3147 [1-10])