Cain And Abel 

One day Eve gave birth to Cain and Abel and when they grew up, Abel became a shepherd and Cain became a farmer. When it was time to bring their offering to the Lord, Cain offered some fruit from the ground and Abel offered his best sheep.

The Lord accepted Abel and his offering but he rejected Cain and his offering. This made Cain very mad.

"Why are you mad?" The Lord asked Cain. "If you do good, I will accept you.  If not, sin is waiting for you, but you must rule over it."

Cain spoke to his brother Abel and said, "Let's go out to the field." When they went out to the field, Cain attacked Abel and killed him. Later the Lord said to Cain. "Where is your brother Abel?" "Am I my brother's keeper?" asked Cain. Then the Lord said, "What have you done? Your brother's blood is like a voice that cries out to me."

Since Cain killed his brother, he had to work the ground. And no matter how hard he worked, the ground would not produce good crops for him. Cain also had to wander the earth. But Cain thought his punishment was very severe and that if he's going to be a wanderer that someone will kill him. But God placed protection over Cain so that no one will harm him.

Why do you think Cain killed Abel?