Arcana Coelestia # 779
779. They went in to Noah into the ark' means that they were saved. This has been stated already. As for 'two and two' meaning pairs, and what they are, see the previous chapter at 6:19.
Genesis 6:19
19
Of every living thing of all flesh, you shall bring two of every sort into the ship, to keep them alive with you. They shall be male and female.