Hebrews 8:6-7

But as it is, Christ has acquired a [priestly] ministry which is more excellent [than the old Levitical priestly ministry], for He is the Mediator (Arbiter) of a better covenant [uniting God and man], which has been enacted and rests on better promises. For if that first covenant had been faultless, there would have been no occasion for a second one or an attempt to institute another one [the new covenant].