Genesis 3-6 is a case study in why I should learn Hebrew! I'm not claiming I understand everything going on in this section of Genesis but what I do understand points me to Jesus.
Genesis 4 starts with the classic sibling rivalry and we learn that people know they should bring offerings to God. We're not given the specifics of that or when they learned about it. We also see that God has a standard for offerings and that He is the judge of them.
Then confusion, who are these other people who might kill Cain? What is the mark God put on him? Who are the nephalim? How much time has passed until God lost patience with mankind? And what's the point of it all!?
Don't skip the genealogy! A little gem left for us right here in plain site is the meanings of the names.
Seth =compensation(to make, fix)
Kenan= possession(room, nest)
Mahalaleel = praise of God(ram, sacrifice)
Jered= descent(come down)
Methuselah=man of the dart(make, to extend)
Add a couple of articles and this is a pretty powerful statement:
The first man was to make mankind a possession ready for the praise of God/sacrifice come down dedicated to extend powerful rest.
Then we get a beautiful picture of God's redemptive plan. God tells Noah to enter into death to save life. Get into a box(don't think a curved ship intended to break through waves, think long rectangular wooden box, remind you of anything? Maybe a coffin?). This box is covered with kaphar(atonement) within and kopher(ransom) without.
We also see a deeply personal God who walked with Enoch and took him away to heaven. A God who was pleased with Noah. Who made a way for mankind to be saved.