Probably the best known controversy of the 21st Century so far is the storm created over the doctrine of Penal Substitution, the idea that Christ was punished for our sins. His flesh, our sins. Our death conquered by His life. Without the shedding of blood, there is no forgiveness of sins. So is this a post enlightenment idea? Is this a Pauline idea? Is it an idea thrown together from a few obscure New Testament texts? Or does it appear to occur from almost the first page of the Bible?
Genesis 1-3, creation: good, man: very good. Serpent, fall, sin, exile. There's no need for blood to be shed for the forgiveness of sins until Genesis 3. What happens just as Adam and Eve are thrown out of the Garden? God clothes them. Oh grace! Your leaves are no good, have some animal skins...animal skins? So animals died, and, presumably, shed blood. So as soon as we see sin, we see it's consequences, the shedding of blood. Interesting.
Later on we meet Cain and Abel. The search for the seed is on... is it one of these two. We learn that Abel was the keeper of the sheep, and Cain the worker of the ground. Both bought the fruit of their labour to God as an offering. Abel; the firstborn of the flock, Cain; some fruit. 'The LORD has regard for Abel and His offering, but for Cain and His offering, He had no regard' (Gen 4:4).
This presents a huge problem unless more than meets the eye is going on here. You could easily read this passage, and see God as a moody god who had gotten out of bed on the wrong side and had decided to take it out upon Cain. That is bad news for Christians, that is no sort of God. Unless...unless Abel's offering was regarded because it was a lamb, a firstborn, an offering that needed the shedding of blood.
We're not told if Abel knew this, or if he just lucked out...but we're not even told why they were offering to the Lord, Genesis is as Genesis does, that's it's beauty. People didn't begin to call upon the name of the Lord until the end of the chapter, when Abel's brothers were born.