Genesis 4:15

Therefore, whosoever slayeth Cain.

God gave him the promise of protection in the threat of seven-fold vengeance upon his slayer. He had taken the punishment of Cain out of the hands of men and was dealing directly with the offender himself. It was needful to restrain private retaliation by. severe penalty. It is not probable that any civil government yet existed, and hence human punishment could not be visited according to the forms of law.

The Lord set. mark on Cain.

The best authorities render it, "Set. sign for Cain;" gave him. sign or token that he should not be slain, as the rainbow was made. sign to Noah, and circumcision to Abraham. It was. guaranty that would quiet his fears.