Genesis 4-7 The first children of Adam and Eve. They had some relationship with God and even knew about worship and sacrifice. Both Cain and Abel bring offerings to God: one is acceptable and one not.

However God tells Cain that he knows what to do. How often do we know what to do but fail to do it?
When God corrects us, do we get angry about it?

Cain ends up killing his brother because Cain is mad and angry at God. Instead of killing a sacrifice and offering it to God, Cain decided to try to rid himself of reminders of God.
We should never take matters into our own hands. When we know the right things to do, simply do them.

Note the passage:”So it came about in the course of time that Cain brought an offering to the Lord from the fruit of the ground. Abel, on his part also brought an offering, from the firstborn of his flock and from their fat portions. And the Lord had regard for Abel and his offering;”
Genesis 4:3-4 NASB2020
https://bible.com/bible/2692/gen.4.3-4.NASB2020

We are told that Abel brought of the firstborn, a blood offering while Cain brought fruit from the ground. Chain’s offering was without blood and possibly not the “first fruits”. Consider the importance of this symbolism throughout scripture.
We find here that God has already demonstrated to people how He is to be worshipped.

Even after Cain murders Abel, God shows grace by not allowing anyone to kill Cain. He marks him with some special grace. Remember that mercy is withholding a judgment deserved and grace is giving a blessing undeserved. God is showing Himself to be full of both mercy and grace.

In these chapters there is also the snapshot info about the Nephilim. These are the “sons of God” known as fallen angels who have sexual relations with the daughters of man. There is much speculation about who these are and what happens with them. It is possible that they created a special type of being through their relationships that were types of giants in the land. It’s possible that these fallen angels were trying to infiltrate God’s world and destroy His plan of redemption. Yet we see how God used Noah and his family to clear the planet of the corruption.
God’s plan prevailed over the wickedness on earth.

This is another aspect of God to remember: no matter how corrupt the world is, God is still in control. God still has people on earth doing His will regardless of how many are not doing His will. God is able to work mightily through one person!

There is also the picture of Enoch walking with God. Enoch who is part of the corrupt world manages to have an incredible relationship with God and to be so close with God that God takes him out of the world. Regardless of how things are in the world, we too can be committed to walking with God. God desires to have a close relationship with us all. We simply must commit to walking with Him continually.