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20 And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven.
16 The day is thine, the night also is thine: thou hast prepared the light and the sun.
To be fruitful relates to goodnesses, and to be multiplied, truths.
(References: Arcana Coelestia 1014, 1018)