Arcana Coelestia #21
21. Verses 4-5 And God saw that the light was good; and God made a distinction between the light and the darkness. And God called the light Day, and the darkness He called Night.
The light is called good, because it comes from the Lord, who is good itself. 'The darkness' is those things which were there prior to the person's new conception and birth. They were seen as light, because evil was seen as good, and falsity as truth. But in reality they are darkness and things proper to that person which are lingering on. All things that are the Lord's, being things of light, are compared to the day, and all that are man's own, being those of thick darkness, are compared to the night, as is done many times in the Word.
Arcana Coelestia #3252
3252. 'A hundred and seventy-five years' means the things constituting that state. This becomes clear from the fact that every number used in the Word means some real thing, see 482, 487, 575, 647, 648, 1963, 1988, 2075, 2252, and so with this particular number which consequently means the things which constitute the state that is the subject here. As long as the mind confines itself to the historical sense it seems as though numbers, such as these 1 which give Abraham's age, do not hold any interior meaning within them. The fact that they do nevertheless hold such meaning within them is evident from all that has been shown already concerning numbers, and becomes clear from the consideration that no number as to its numerical value contains anything holy, and yet the smallest detail of all in the Word is holy.
Footnotes:
1. i.e. the numbers 100, 70, and 5