Taken from a teaching on Genesis 4-5:
I think the most significant lesson we can gain from these two chapters comes in the story of Cain and Abel and the offerings they brought to God.
Verse 4 (The Message) says: "Cain brought an offering to God from the produce of his farm. Abel also brought an offering, but from the firstborn animals of his herd, choice cuts of meat."
Now to you and me that sounds great! Cain was a farmer and he brought God an offering from the produce from the land: the work of his hands, which looks fine at first glance. Abel brought an offering of choice pieces of a firstborn lamb.
We wouldn't even know that there was a problem in this story, except we're told in verse 4 (TM): "God liked Abel and his offering, but Cain and his offering didn’t get his approval."
Cain's offering of the produce of the ground was rejected. Abel's offering of the pieces of a slain firstborn lamb was accepted. Does any of this sound familiar to you?
Abel believed, Cain did not. And in some way, seen only by God, Abel was looking to Calvary and the work Jesus accomplished there.
Heb:11:4 says: "By faith Abel offered to God a better sacrifice than Cain, through which he obtained the testimony that he was righteous."
Oswald Chambers talks about this concept in one of his devotions. Listen to what he says:
"It does not matter who or what we are, there is absolute reinstatement into God by the death of Jesus Christ and by no other way, not because Jesus Christ pleads, but because He died. It is not earned, but accepted. All the pleading which deliberately refuses to recognize the Cross is of no avail; it is battering at another door than the one Jesus opened."
How do I approach God? Am I coming to Him through the door Jesus opened, accepting the sacrificial death of Jesus as the atonement of my sins? Or am I trying to find acceptance with God through that other door--you know, the one where you work to please God?
I battered at that "other door" for many, many years. I understand what it is, completely. I had asked Jesus to be my Savior but still found myself working and hoping to find His favor. Ultimately I broke through to the truth of the matter...
I don't need to work to approach God.
I don't need to work to find His favor.
I'm already in His favor because of the work Jesus did on the Cross!
If you've gone to Jesus and received the work He did on the cross for you, then you are in God's favor, and you can approach Him freely at any time, based on the work of the Cross.
I assure you, the enemy will keep us working for favor as long as he can keep us thinking that is what is required. But that is battering at another door. Jesus said, "I am the door; if anyone enters through Me, he will be saved, and will go in and out and find pasture." John 10:9