"The man has intercourse with his wife Eve, and she conceived and gave birth to Cain, 'I have acquired a man with the help of Yahweh,' she said. She gave birth to a second child, Abel, the brother of Cain. Now Abel became a shepherd and kept flocks, while Cain tilled the soil. Time passed and Cain brought some of the produce of the soil as an offering for Yahweh, while Abel for his part brought the first-born of his flock and some of their fat as well. Yahweh looked with favor on Abel and his offering. But he did not look with favor on Cain and his offering, and Cain was very cross and downcast. Yahweh asked Cain, 'Why are you angry and downcast? If you are doing right, surely you ought to hold your head high! But if you are not doing right, Sin is crouching at the door hungry to get you. You can still master him.' Cain said to his brother Abel, 'Let us go out'; and while they were in the open country, Cain set on his brother Abel and killed him.
"Yahweh asked Cain, 'Where is your brother Abel?' 'I do not know,' he replied. 'Am I my brother's guardian?' 'What have you done?' Yahweh asked. 'Listen! Your brother's blood is crying out to me from the ground. Now be cursed and banned from the ground that has opened its mouth to receive your brother's blood at your hands. When you till the ground it will no longer yield its strength to you. A restless wanderer you will be on earth.' Cain then said to Yahweh, 'My punishment is greater than I can bear. Look, today you drive me from the surface of the earth, I must hide from you, and be a restless wanderer on the earth. Why, whoever comes across me will kill me!' 'Very well then,' Yahweh replied, 'Whoever kills Cain will suffer a sevenfold vengeance.' So Yahweh put a mark on Cain, so that no one coming across him would kill him. Cain left Yahweh's presence and settled in the land of Nod, east of Eden."
From The New Jerusalem Bible