In Hebrews 9:15-22 the author explains the significance of Christ being the mediator of the new covenant. As the mediator of the covenant He had to die to instituted the testamentary aspect of the covenant. Is the new covenant a testament? Yes, because it grants the right to an inheritance. The glory of the mediator is seen in that by His blood this inheritance is now in place for His people and by that same blood He has cleansed us from our sins. This is the glory of the mediator.