And the Lord said to him: "By no means will it be so; rather, whoever would kill Cain, will be punished sevenfold." And the Lord placed a seal upon Cain, so that anyone who found him would not put him to death
Other versions
King James Version
And the LORD said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the LORD set a mark upon Cain, lest any finding him should kill him.English Standard Version
Then the LORD said to him, "Not so! If anyone kills Cain, vengeance shall be taken on him sevenfold." And the LORD put a mark on Cain, lest any who found him should attack him.New International Version
But the LORD said to him, "Not so; if anyone kills Cain, he will suffer vengeance seven times over." Then the LORD put a mark on Cain so that no one who found him would kill him.