Another of Doré's woodcuts.
So...the first death recorded in the Bible is the death of some non-specific animals to provide a covering for Adam and Eve.
The next death is also a sacrifice: Abel offers a sacrifice to God from his sheep; Cain, an unbloody sacrifice from his crops:
Now Adam knew Eve his wife, and she conceived and bore Cain, saying, “I have gotten1 a man with the help of the Lord.” 2 And again, she bore his brother Abel. Now Abel was a keeper of sheep, and Cain a worker of the ground. 3 In the course of time Cain brought to the Lord an offering of uthe fruit of the ground, 4 and Abel also brought of vthe firstborn of his flock and of their fat portions. And the Lord whad regard for Abel and his offering, 5 but xfor Cain and his offering he had no regard. So Cain was very angry, and his face fell. 6 The Lord said to Cain, “Why are you angry, and why has your face fallen? 7 yIf you do well, will you not be accepted?2 And if you do not do well, sin is crouching at the door. zIts desire is for3 you, but you must rule over it.” --Genesis 4:1-7We aren't told here exactly why Cain's sacrifice was not accepted, but Abel's was. There are several theories (I like how Richard Harris in John Houston's The Bible skimps on what he gives), but none explicit here in Genesis. But the author of Hebrews mentions this:
4 By faith hAbel offered to God ia more acceptable sacrifice than Cain, through which he was commended as righteous, God commending him by accepting his gifts. --Hebrews 11:4So what is the difference? Faith. Though maybe there's a point about Abel offering blood and Cain offering grain, the distinction brought out in the New Testament is not this (even though the writer of Hebrews talks a lot about blood--the word 'blood' occurs 21 times in that book alone). Evidently, Cain's faith was deficient; Abel's faith was sufficient.
So here a new concept is introduced in the redemptive history of the Bible: faith. In the first sacrifice, we saw how God Himself made the first offering to cover Adam and Eve. Now, we see their children offering sacrifices from the fruit of their labors. But one offered by faith, and was accepted; whilst the other did not have this faith...and was not accepted.
But what is faith? So often today, in religious contexts, "faith" simply means "belief". However, this is the merest necessity for faith. Sure, faith includes belief, in the same way knowledge includes belief. But it's not faith merely to believe in the existence of something. Faith, rather, is placing one's trust in someone or something else. It is not always a wise choice; faith can be betrayed or unfulfilled. Mere belief does not necessitate faith--I can intellectually believe in someone's trustworthiness--but entrusting them with something of value demonstrates that I have faith in them.
The question of belief in God is rarely addressed in the Bible (it's generally presumed, but note Heb 11:6); but the question of faith is something else entirely. Evidently, Cain heard God's voice, so it's doubtful that he disbelieved in Him...but it's also evident that he didn't trust Him.
Though one can certainly have faith in an impersonal object, we generally don't use that term. And in the Bible, faith is placed in persons (or more specifically, a Person). Biblical faith is inherently relational. God is there, saying 'I am your God. Put your faith in Me.' Rich relational imagery is used in Scripture--God the Husband, God the Father, even God the Mothering hen. Our faith is not a cold calculation, like tentatively stepping out on a bridge to see if it will support our weight; no, it is like a marriage, where we become willingly vulnerable to Another.
With God, it is both easier--and harder--than putting faith in another human. It is easier, if we believe that He is fundamentally good, and looking out for our highest good. It is harder, in that He is so utterly more powerful, more vast, more unsearchable than anyone else. To trust in God is diving into a sea without a shore:
Yet in the end, we have no recourse. We are subject to His power, whether we trust in Him or not. And trusting in Him challenges us to re-examine our time-bound preconceptions and any sense of entitlement we might have. He is not your President, or your Therapist, and He certainly isn't your divine servant doing whatever you ask. He is King of kings and Lord of lords.
He isn't an American, nor is He the Champion of liberal democratic virtues. Our concepts of right and wrong, justice, and value (which are continually changing) are nothing in His sight. Do not be surprised if you don't find Him cheering for your favorite cause de jour.
So...this element of faith is also central to the divine narrative. But there's also much more; we've barely begun looking through the Bible on this concept of the Atonement.