Cain and Abel, sons of Adam (peace be upon him).

When Adam (peace be upon him) settled on earth and his offspring began to populate it, Eve started giving birth to twins, a boy and a girl, in each pregnancy. One day, she gave birth to twins and Adam named the boy Cain, and later she gave birth to another set of twins and named the boy Abel. As time passed, Cain and Abel grew up. According to Adam's law, a son was not allowed to marry his sister who was born in the same womb, but he could marry his sister who was born before or after him.

One day, Abel wanted to marry Cain's twin sister, and Adam agreed, but Cain refused and wanted to marry his own twin sister because she was more beautiful than Abel's twin sister. Satan continued to plant hatred and envy in Cain's heart towards his brother, which is Satan's ultimate goal since the creation of Adam - to deceive all of Adam's children because they are his eternal enemies.

To resolve the issue, Adam ordered both of them to offer a sacrifice to God, and whoever's sacrifice is accepted would marry Cain's twin sister. Cain offered some of the worst crops, while Abel offered a fat sheep from his livestock. Fire came down from the sky and consumed the sheep, indicating that God accepted Abel's sacrifice but not Cain's. Cain became very angry, and Satan tempted him to kill his brother Abel. Abel didn't want to harm Cain because he knew that if he did, God would be very angry with him.

After killing Abel, Cain didn't know how to dispose of his brother's body since this was the first crime on earth, and no one knew how to bury the dead. God sent two crows fighting each other, and one killed the other. Cain saw the killer crow bury the other and followed suit, burying his brother. Cain felt great regret for what he had done to his brother.

This story highlights the struggle between good and evil and the importance of obedience to God's commands.