What religion or worship system existed before the Law was given?
Before the Law was given at Mount Sinai, 2,500 years after Adam was created, there was no system of worship and no organized religion. No written 'Thou shalt' or 'Thou shalt not' existed, and humanity's thoughts were only evil continually.
Les explains that up until the Law was given at Mount Sinai—2,500 years after Adam—there was no system of worship, no organized religion as we call it, and no written 'Thou shalt' or 'Thou shalt not.' The Law was added because of transgressions, or sin. Before it, sin ran rampant. Genesis 6:5 illustrates this: God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually. Les notes that this shows all people could think about were evil, wicked, and dishonest things, always trying to cook up a crooked deal.