Seeing the foundation of later Biblical theology in the creation account is easier in retrospect. Much like the sixth chapter of John, subsequent revelation causes the unclear to become absolutely clear. Indeed, this is so much the case, that after the larger picture is complete, not recognizing the earlier snapshots becomes a great loss.
For instance, why does Gen. 2:11-12 go into what seems like a parenthetical statement about the land of Havilah and the jewels that are there? Should I even ask this question?
As we read on, we see that it was while in the Havilah area (around Sinai in Shur- 1 Sam. 15:7) that Israel first found the bdellium-colored manna, and we also see that gold and onyx were used to built the Tabernacle and the High Priestly garments (Genesis 2:12; Exodus 25:7; 28:9-12; Numbers 11:7).
Bdellium has a relation to manna, which itself gained sacramental significance as it was kept in the tabernacle. Paul also appeals to it in 1 Cor. 10 as a counterpart to the Christian sacraments. Gold and onyx are Tabernacle jewels, and thus we have more support to the already well-accepted notion that the Garden of Eden was the tabernacle and temple in seed form.
This theme is carried out through Genesis 1, Genesis 2-3, and Genesis 4. Cain is a “man” who works in the dirt. Abel, literally “vapor,” is a shepherd whose sacrifice is appropriate. Dirt (earth), vapor (heaven), and sacrifice are all embedded in Genesis 4, coming right on the heels of the symbolically-charged garden of Eden (Eden is later explicitly connected with God’s holy mt.- Ez. 28:14).
And this is also important because creation ideas are later incorporated into Israel’s worship. God dwelled on the mountain for six days before calling Moses to enter his presence on the seventh. Unleavened bread is consumed for six days during Passover before the people draw into the assembly of the Lord on the seventh. The feast of tabernacles lasts for seven days. Priests were ordained for seven days (Ex. 29:35).
And of course, the Christian calendar ought to follow the new creation, which is the life of Christ.
Essentially, origins make for identities.