• Genesis 4:10-15
  And He said, “What have you done? The voice of your brother’s blood cries out to Me from the ground. So now you are cursed from the earth, which has opened its mouth to receive your brother’s blood from your hand. When you till the ground, it shall no longer yield its strength to you. A fugitive and a vagabond you shall be on the earth.” And Cain said to the LORD, “My punishment is greater than I can bear! Surely You have driven me out this day from the face of the ground; I shall be hidden from Your face; I shall be a fugitive and a vagabond on the earth, and it will happen that anyone who finds me will kill me.” And the LORD said to him, “Therefore, whoever kills Cain, vengeance shall be taken on him sevenfold.” And the LORD set a mark on Cain, lest anyone finding him should kill him.
   
• Genesis 9:5-6
  Surely for your lifeblood I will demand a reckoning; from the hand of every beast I will require it, and from the hand of man. From the hand of every man's brother I will require the life of man. "Whoever sheds man's blood,
  By man his blood shall be shed;
  For in the image of God
  He made man.
   

Related Scriptures

• Hebrews 10:4
  For it is not possible that the blood of bulls and goats could take away sins.
   
• Matthew 5:21-22
  "You have heard that it was said to those of old, 'You shall not murder, and whoever murders will be in danger of the judgment.' But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, 'Raca!' shall be in danger of the council. But whoever says, 'You fool!' shall be in danger of hell fire.
   
• Matthew 26:52
  But Jesus said to him, "Put your sword in its place, for all who take the sword will perish by the sword.
   
• Exodus 21:12
  “He who strikes a man so that he dies shall surely be put to death.