Adam and Eve’s sons, Cain and Abel, had very different personalities. Cain enjoyed farming, while Abel cared for flocks. After sin entered the world, God established a sacrificial system where the shedding of blood was required for forgiveness. Abel followed God’s command and offered a lamb as a sacrifice, but Cain, feeling it unnecessary, offered produce from his fields instead. God accepted Abel’s offering but rejected Cain’s, causing Cain to become jealous and angry. Despite God’s warning and Abel’s attempt to reason with him, Cain killed Abel. God cursed Cain and marked him to prevent revenge. This story foreshadows a future conflict over worship in the last days, where people will be marked either by the seal of God or the mark of the beast.