During the Age of Knowledge, God spoke to man through the written law. His boundaries defined relationships between people, between man and his environment, and between man and his God. But because the fullness of time has now come, God today speaks to all creation by and through His Son. We claim Christianity as different from all other religions in that each person can have a personal relationship with a Personal God.
This is a significant differentiation between these two ages:
Under law, man could relate to a Holy God only through measuring up to His standards and keeping His commandments, by performing certain behaviors. So to maintain this surface relationship you always had to be on your best behavior.
Not so in the Age of Grace. Because God created us now to be His sons, we are members of His family. Often times we are in relationship with God IN SPITE OF our behavior. He has given us a new heart, a new nature, and a new identity. In the age to come, He will continue to speak through His Son; it will simply be a corporate or multi-membered mature son.