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26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
4 And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female,
'Three' denotes fullness, and 'a third,' not full.
(References: Arcana Coelestia 2788 [1-13])