Separate from the above, if Moses was the only mediator of the Mosaic Covenant then no one would be saved or be lead to Christ by it. Moses evidently saw it differently. He pointed to Christ as the mediator between God and man. No one else is given that ultimate privilege. We can all pray and mediate as priests before God as the New Covenant Commands. If this was not true for the Old Covenant saints also in some form then why should they pray? God had a means. He set the rules. Christ was the promise and fulfillment in both testaments and Covenants. They are the same in substance if you ask me. But I am still working on it.