Adam and Eve had two sons after they left the garden. Able was a keeper of sheep and Cain was a farmer.

In due time the brothers made an offering to the Lord, Abel, brought of the firstlings of his flock and of the fat thereof. And the LORD was pleased with Abel and his offering:

Cain brought of the fruit of the ground for an offering unto the LORD but with Cains offering He was not pleased. The Lord required that the lifeblood of an animal be shed for an offering.

This mad Cain angry, but God said, don't be angry Cain. I will be pleased with you when you bring the right offering. Cain could not get over his angry. When he and his brother Abel were in the field he killed his brother.

Later the LORD said unto Cain, Where is Abel thy brother? And he said, I know not: Am I my brother's keeper? But God knew what Cain had done. He placed a mark on Cain's forehead and took away his ability to grow crops. He was driven away by the Lord from his home land and lived in the land of Nod, there he married and began building a city.