Genesis 4 Cain and Abel  - a farmer and a shepherd;  both successful and fruitful in their work; both prepared an offering to bring to the Lord.

Cain's offering came from - the "fruit of the ground". 
Abel's offering came from- "the firstling of his flock and of their fat portions". 

"The Lord had regard for Abel and for his offering; but for Cain and for his offering He had no regard."  Abel's offering was a true sacrifice. It was offered in faith we are told in Hebrews 11:  "By faith Abel offered to God a better sacrifice than Cain, through which he obtained the testimony that he was righteous, God testifying about his gifts, and through faith, though he is dead, he still speaks."

Cain's offering was not offered in faith.  He became angry and jealous. The Lord spoke to Cain and warned him that "sin is crouching at the door; and its desire is for you, but you must master it." 

But, Cain didn't resist.  Instead, he plotted and killed his own brother.  Like always, sin gains nothing and loses everything. Cain, the proud farmer, is cursed so that he can no longer cultivate the ground.  He is sent out to be " a wanderer on the earth ".  Even then, Cain does not repent.

Cain goes out and builds a city.  He becomes a father and a grandfather and a great-grandfather.  His offspring become ranchers, musicians, and metal workers.  Five generations later, Lamech exceeds Cain's sinfulness by taking two wives and by killing two people and bragging to his wives about it.
The Bible Knowledge Commentary says this, " Lamech altered the plan of God and married two women. His family produced musical instruments and implements to make life enjoyable.  But in spite of this prosperous good life, evil was advancing ominously. ... So here is a picture of an affluent society defying God and His laws, seeking pleasure and self-indulgence. "

Meanwhile, Adam and Eve give birth to Seth.  It is during the life of Seth's son Enosh that "... men began to call upon the name of the Lord."  It is from Seth's line that faith is preserved and righteousness is possible.

Father in heaven, once again You lead us by Your Word to remember and to be encouraged to abide in You, to be obedient to the Word, to hold on to Truth and Life through faith.  Your will be done, Lord !  Keep us in Your Hand.  Increase our love and fill us with Your Spirit every day. Amen.