Here are some excerpts from Swedenborg's "Arcana Coelestia" that help explain the inner meaning of this chapter:

AC 1890. The subject treated of in this chapter is the Lord’s first rational, which was conceived by the influx of the internal man into the affection of memory-knowledges (scientiae) of the external. The internal man is "Abram;" the affection of memory-knowledges in the external is "Hagar the Egyptian handmaid;" the rational thence derived is "Ishmael." The nature of this rational is here described; and it is afterwards said (chapter 21); that it was expelled from the house, after the Lord‘s Divine rational, represented by Isaac, had been born.

AC 1891. The Lord’s first rational was conceived according to order by the influx or conjunction of the internal man with the life of the affection of memory-knowledges belonging to the external (verses 1 to 3). But as this affection was of the external man, its nature was such that it held intellectual truth in low esteem (verse 4). On which account the Lord thought concerning the subjugation of it (verses 5 to 9), and that when subjugated, it would become spiritual and celestial (verses 10, 11). What it would be if not subjugated, is described (verse 12); the Lord‘s insight into the cause from His interior man (verses 13, 14). The rational is thus described in respect to its quality; also the Lord’s state when it originated (verses 15, 16).

1889. It is similar in this chapter with the names Abram, Sarai, Hagar, and Ishmael. What these include within themselves becomes clear from the Contents and after that from the explanation of each name in what follows. They are however things such as cannot be explained easily and intelligibly, for the subject covered by those names is the Lord's Rational - how it was conceived and born, and the nature of it before it had been united to the Lord's Internal, which was Jehovah. The reason this cannot be explained easily and intelligibly is that people at the present day do not know what the internal man is, what the interior man is, or what the exterior man is. When one speaks of the rational or of the rational man some idea can be formed of these, but when one speaks of the rational as that which lies between the internal and the external, few if any can grasp it. Nevertheless since the subject in the internal sense of this chapter is the way in which the Lord's Rational Man was conceived and born from an influx of the Internal Man into the External Man - for this is the subject embodied within the historical descriptions involving Abram, Hagar, and Ishmael and yet to prevent the ideas presented in the explanation that follows from becoming utterly strange and unintelligible, let it be recognized that with everyone there exists an internal man, there exists a rational man which is situated in between, and there exists an external man, and that these three are quite distinct and separate from one another. For these matters see what has been stated already in 978.