James 2:10 For whoever shall keep the whole law, and yet stumble in one point, he is guilty of all.
If we were to rely just on the scriptures from the Old Testament we would very quickly find out that we fall short of the rules and regulations; which makes us guilty of everything!
But those same scriptures point to a Messiah which would solve this problem for us by coming to take away that sin debt from us when we truly believe on Him.
Christ came to fulfil that prophecy and now we do have to take on that truth so that we will be able to be forgiven and be not guilty before God!