Cain said to Abel his brother, “Let us go out to the field.” And when they were in the field, Cain rose up against his brother Abel, and killed him. Then the Lord said to Cain, “Where is Abel your brother?” He said, “I do not know; am I my brother’s keeper?” And the Lord said, “What have you done? The voice of your brother’s blood is crying to me from the ground. And now you are cursed from the ground, which has opened its mouth to receive your brother’s blood from your hand. When you till the ground, it shall no longer yield to you its strength; you shall be a fugitive and a wanderer on the earth.” Cain said to the Lord, “My punishment is greater than I can bear. Behold, thou hast driven me this day away from the ground; and from thy face I shall be hidden; and I shall be a fugitive and a wanderer on the earth, and whoever finds me will slay me.” Then the Lord said to him, “Not so! If any one slays Cain, vengeance shall be taken on him sevenfold.” And the Lord put a mark on Cain, lest any who came upon him should kill him.
(Gn 4, 8-15)