I don't think a true christian should not believe in the old testament.Christianity in the light of christ phenomenon should mean the severing of the new from the old,a new beginning,hence the statement,IT IS FINISHED

So from whatever level u are taking it from,u should put the past aside and forge a new concept and meaning,a redefinition of what has been,what is,what will be and what could be.It is the story of life itself,change.