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12 And the earth brought forth grass, and herb yielding seed after his kind, and the tree yielding fruit, whose seed was in itself, after his kind: and God saw that it was good.
6 By the word of the LORD were the heavens made; and all the host of them by the breath of his mouth.
'Three' denotes fullness, and 'a third,' not full.
(References: Arcana Coelestia 2788 [1-13])