“Adam had sexual relations with his wife, Eve, and she became pregnant. When she gave birth to Cain, she said, 'With the Lord’s help, I have produced a man!'”
Adam and Eve were the first people that God created. Their first recorded child was a son named Cain, so he was mostly likely their firstborn son (Genesis 4:1). Their second child listed in scripture was Abel (Genesis 4:2).
Because of Adam and Eve's disobedience, sin and death had entered the world (Genesis 3), which passed onto their children and rippled out into all of humanity.
Two brothers. Two offerings.
“When it was time for the harvest, Cain presented some of his crops as a gift to the Lord. Abel also brought a gift—the best portions of the firstborn lambs from his flock. The Lord accepted Abel and his gift, but he did not accept Cain and his gift. This made Cain very angry, and he looked dejected.”
As adults, Cain worked as a farmer while Abel was a shepherd. When these two brothers brought an offering to the Lord, Cain brought produce and Abel brought a firstborn lamb. The Lord was pleased with Abel’s offering but rejected Cain’s. The Bible doesn't explicitly say why Cain’s offering was rejected, but we do have some hints.
Attitudes of Offering
Two obvious differences in the brothers' offerings are in how they're described. Abel brought "the best portions of the firstborn lambs from his flock" (Genesis 4:4, NLT). And Cain's offering is described as "some of his crops" (Genesis 4:4, NLT). So it's possible that, while Abel brought "the best portions," Cain simply brought a portion of regular crops.
Since God looks at the heart (1 Samuel 16:7), it's possible that God rejected Cain’s offering because he had the wrong heart attitude. Authentic worship isn't just an outward display but a matter of authentic faith in a person's heart (1 Samuel 15:22; Hosea 6:6).
Types of Offering
Another obvious difference is that Abel’s offering was an animal (blood) sacrifice, and Cain’s was a vegetable (bloodless) sacrifice. That said, scripture doesn't give an indication that these differences factored into God’s acceptance of Abel and rejection of Cain.
Other Biblical Evidence
“It was by faith that Abel brought a more acceptable offering to God than Cain did. Abel’s offering gave evidence that he was a righteous man, and God showed his approval of his gifts. Although Abel is long dead, he still speaks to us by his example of faith.”
Hebrews 11:4 says that Abel offered his sacrifice in sincere, honest faith and was commended as righteous, so God accepted his gift. Without faith, it's impossible to please God (Hebrews 11:6), so one reason Cain’s offering might have been rejected is because he didn't offer it in obedient faith. Rather than humbly trusting God, he may have thought that he could earn God’s forgiveness with how good his offering was.
But no one can earn God’s forgiveness through behavior. Our good works are as potent as "filthy rags" when it comes to earning salvation (Isaiah 64:6). We can only be saved through faith in Jesus’ sacrifice for our sin—not through our good works (Ephesians 2:8-9).
Cain's Response to Rejection
“One day Cain suggested to his brother, 'Let’s go out into the fields.' And while they were in the field, Cain attacked his brother, Abel, and killed him.”
Directly after the offering was rejected, God approached Cain about his sad face, saying, "Why are you so angry? Why do you look so dejected?" (Genesis 4:6). God warned him that his refusal to choose God's standards would cause him to lose the battle with sin (Genesis 4:7-8). He had a chance to redeem himself before God, but sadly, Cain chose to remain in his anger and envy.
In a fit of jealousy, the firstborn son of Adam turned to violence. Cain called Abel out into the fields one day and attacked him so fiercely it ended in death. This was the first recorded murder in human history.
In Jude 1:11, "the way of Cain" is referenced in connection with lawless men. 1 John 3:12 says that Cain belonged to the evil one. It's obvious that Cain had no interest in doing the right thing but that his heart was corrupt and would lead him to wicked actions.
God's Response to Cain's Disobedience
“Cain replied to the Lord, 'My punishment is too great for me to bear! You have banished me from the land and from your presence; you have made me a homeless wanderer. Anyone who finds me will kill me!'”
Because of Cain’s sin, God put a curse on him. As a farmer, Cain relied on the ground to cooperate with his efforts, but God made it so that the soil would no longer produce for him. Unfortunately, this consequence condemned Cain to a life of wandering, far from the presence of God (Genesis 4:11-13).
In a final plea to the Lord, Cain expressed he was afraid someone would kill him to get revenge for killing Abel (Genesis 4:14). In an act of absolutely undeserved mercy, God chose to protect him. He put a special mark on Cain so that anyone who tried to attack him would know that the Lord would punish them seven times over (Genesis 4:15-16). Though Cain would live under the curse of his sin for the rest of his life, no one would kill him for his crime.
The Legacy of Cain
“Cain left the Lord’s presence and settled in the land of Nod, east of Eden.”
After all this happened, Cain married, had children, and built a city called Enoch, named after his son (Genesis 4:17). The descendants of Cain became people who raised livestock, crafted musical instruments, and built tools of bronze and iron (Genesis 4:20-22). Like their father, the descendants of Cain followed in his steps of wickedness (Genesis 4:23), which is why there was so much evil in the world by the time of Noah (Genesis 6).
In Noah's time, the wickedness on the earth was so great that God would destroy all of humanity through a flood. Noah was a righteous man who was descendent of Seth, Adam and Eve's third son. Only this man and his family would be saved by building an ark at God's instruction, and they would be the ones to begin a new population in the world (Genesis 6:9-22).