'Skins' or 'hides' signify external things, because the hide is the outermost organ of an animal where its interiors extend, the same as with a person's dermis or skin. 'Skin' corresponds to truth or to falsity in the extremes. See Arcana Coelestia 1835, 10036, and Apocalypse Explained 386. 'Skin,' as in Job 19:26, means the natural degree a person has with him after death.

In Exodus 22:27, this signifies things that are relatively external. (Arcana Coelestia 9215)

In Exodus 34:29, this signifies the internal of the Word shining from the external. (Arcana Coelestia 10691)

In Job 19:20, this signifies being not entirely in falsities. (Apocalypse Explained 556[11])

In Jeremiah 13:23, this signifies that evil cannot change its nature. (Apocalypse Explained 780[5])

In Genesis 3:21, this signifies that the Lord instructed them in spiritual and natural good. (Arcana Coelestia 292)

In Genesis 27:16, this signifies the external truths of domestic good. (Arcana Coelestia 3540)

5497. 'And it was in the mouth of his pouch' means that it was returned as a gift and was put back in the opening of the exterior natural. This is clear from the meaning of 'the mouth of the pouch' as the opening of the exterior natural. Its having been put back there is implied from its very presence there, while its return as a gift follows from what was stated immediately before this, that no power of their own had been expended. Because 'the pouch' was in the preliminary part where the sack opened, nothing else is meant by 'the pouch' than the preliminary part of the receptacle, which is the exterior natural since this too is a preliminary part - 'a sack' being a receptacle, see 5489, 5494. So that anyone may know what the exterior natural and the interior natural are, let a further brief statement be made about them.

[2] One who is still a child cannot begin to think from anything higher than the exterior natural, for he composes his ideas out of sensory impressions. But as he grows up, employing sensory impressions to work out the reasons for things, he begins to think from the interior natural. For he begins to employ his sensory impressions to formulate ideas about truths which essentially are higher than sensory impressions; yet such ideas are still on a level with things in the natural world. But as he grows into a young adult, if he develops his power of reason, he employs what is in his interior natural to work out the reasons for things, which are truths of a yet higher nature. These are extracted so to speak from what is present in the interior natural. (The learned world calls the ideas composing thought which originate in this way intellectual and immaterial ideas, whereas ideas formed from factual knowledge present in both parts of the natural, insofar as these originate in the world and come through the senses, they call material ideas.) This is the manner in which a person rises with his understanding from the world up to heaven. Yet he does not go on into heaven with that understanding unless he accepts good from the Lord which is constantly present and flowing into him. If he does accept that good he is also endowed with truths, for in good all truths are welcome guests. And as he is endowed with truths, so he is endowed with understanding enabling him to have his being in heaven.