The way of Cain: why was Cain's sacrifice rejected?

And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD. And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground. And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD. And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering:

But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell. And the LORD said unto Cain, Why art thou wroth? and why is thy countenance fallen? If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him. Genesis 4:1-7

The two sons that came forth from Adam are not his children alone. Now please do not think that I am giving any credence to the fable of the serpent seed story but instead we must keep in mind that we are all born after the “kind” of Adam. This being true what came forth from Adam comes forth from us also.

For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart. 13Neither is there any creature that is not manifest in his sight: but all things are naked and opened unto the eyes of him with whom we have to do. Hebrews 4:12

I believe that these stories are literal yet they were not given to us for the sake of literal facts but instead as examples. they bring those with open eyes and ears to knowledge of themselves, of their creator, of their redeemer, and of their redemption.

The why of given scripture is the understanding that affects beyond our thoughts to our being. A mental and analytic determination of the facts may change what we believe to be acceptable or unacceptable.This acceptance could lead a man to attempt to act as he should. Understanding of why leads us to a place where the only decision is to be different; which we come to know can only be effected by something beyond ourselves through faith.

So what is the why of Genesis? The word of YHWH is a living word but it was necessary to write down a witness of that word so that it could not be changed; which Moses began at Sinai. 
If left to men the how becomes very muddled. We see this at the tower of babel when men first organized an apostate religion; spreading out from that central access point to be embellished by the many groups to form the pagan worship system. 
Moses gives at the outset a debunking of the multitude of creation myths and the pantheon of gods they birthed. There is one creator, one giver of life, wisdom, and might and YHWH is one.

And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons Genesis 3:7

For if he that cometh preacheth another Jesus, whom we have not preached, or if ye receive another spirit, which ye have not received, or another gospel, which ye have not accepted, ye might well bear with him. 2 Corinthians 11:4

For other foundation can no man lay than that is laid, which is Jesus Christ. 1 Corinthians 3:11

We see in Cain the beginnings of building on his father Adams failed man devised foundation. Cain’s god of his own making retains YHWH’s name and his ordinance of sacrifice but is shaped to Cain’s own way of right and wrong instead of life and death.

Decades before YHWH took a skin and replaced the fig leaf aprons of Adam’s design with a covering for man’s nakedness of His own making. This began the age of mercy when as Paul puts it YHWH winked at sin.
 It was a time bringing us to grace; when the blood of bulls and goats covered sin, just as their skins covered the nakedness of men. 
In the same way that the coat could not change the man within it so also the covering blood could not take away the guilt of its offeror.

These things being established then why did YHWH institute such a grisly ordinance of blood and death if it had no power to take away sin? If it was the faith in YHWH’s promised redemption that has always brought salvation then why the ordinance? The answer is that mental assent of a truth is the deception of man that he dwells in that truth just as actions performed are the deception that he is righteous.

The sacrificial system was the killing of living innocent lambs not to take our sin but a lived out parable teaching us of the horror of sin and the magnitude of the price involved to redeem us.
 Sin is deceptively easy and small until we come face to face with the cost to ourselves and those who we care about.

And almost all things are by the law purged with blood; and without shedding of blood is no remission. Hebrews 9: 22

So is YHWH callous; caring nothing for lambs that are slaughtered just to teach us a lesson? If one would ask this question then consider have any of us ever made a lamb? 
YHWH spoke them into existence and as such they are from the abundance of his heart. However His children are His greatest treasure and at a gruesome cost to himself He has laid put forth a way that goes beyond teaching us what to do and teaches us what we must trust Him to make us become.

The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world. John 1: 29

The understanding of the why we are given the witness of Cain and Able is tied directly to the why of Cain’s sacrifice not being accepted. In the relationship of our being made the righteousness of YHWH we are shown that we offer Cain’s sacrifice much more readily that Abel’s. 
Abel in this story is almost seemingly secondary. Cain is the main character. When the sacrifice is offered we do not see YHWH lavishing attention on Abel but it is instead Cain with whom YHWH spends His time; pleading with Him to understand his need to be given redemption in the way that had been established, offering a chance to be redeemed, and warning him of the results of following after his own way.

What made Cain’s sacrifice unacceptable? Some have suggested that Cain offered those vegetables and fruit that he thought to be subpar; however if this had been the case then shame or guilt should have been the reaction. 
Cain’s murder of passion was an act of anger. If YHWH had rejected something Cain had placed no value in then Cain would have saw the rejection as being for the inferior fruit alone.
 Cain took this rejection all the way to the core of his being.

It is likely Cain worked the soil, seed, plant and fruit with meticulous care and concern and then from them picked the very best. It should be obvious from His reaction that he expected to be accepted and lifted up.
 This way of Cain is still practiced today by most that claim faith in Messiah.
 We decide what we should do for YHWH, the way we will make ourselves pleasing to Him, and what will manifest His blessings in our life; all of these things we take shore up with scripture. Yet they are a facade and a manipulation used that we may be conformed to our perception of right.
We forget (or ignore) that only YHWH is our Elohim (creator) and that as we give up on ourselves and trust Him He makes us what we should be…one with Him.

It is a redemption that must be possessed but can never be paid for. It is offered to all men as grace but that infuriates those who wish to be recognized for the work they have done and the sacrifices they have made to a place of hate and destruction for any who accept it.