The Ramban points out that this Book repeats, with minor changes, not only the Ten Commandments but many other teachings which the people had received earlier, though certain new material is introduced such as the laws of marriage and divorce.
Two important lessons derive from this: as Rav Kook used to say, hayashan yitchaddesh, hechadash yitkaddesh – “The old needs to be renewed; the new needs to be consecrated”.
True, some people are impatient with the past and think that modernity is automatically superior to history, but the fact is that history provides the criteria by which to assess modernity and if necessary to reject some less admirable aspects of the modern way.
How, for example, can anyone think that the pervasive modern forms of selfishness, exploitation of others, addiction and indulgence are superior to the mores and ethics of our Biblical past?
On the other hand, some things that are new can be “consecrated”. New times produce new ways of promoting and furthering the old ideals.
Technological society has created new opportunities for the human mind and heart. The increasing spread of Torah material that the Internet has facilitated is achieving ends which our ancestors could hardly dream of. The growing life span which modern medicine has made possible has given us more time to do good deeds.
So many things are being discovered that we see wonders in Creation which earlier ages never realised were there.
What we need is to be judicious in the way we combine the old and the new, rejecting nothing merely because it is new and using the old to help us decide how much of the new is going to be a blessing.