Jesus Christ's priesthood is superior to the Aaronic priesthood because Christ tenure is eternal rather than temporal, guaranteeing both continuity and quality. Hebrews 7 is the only portion of scripture that carefully examines Christ's credentials as High Priest, giving us concrete hope of our salvation. His blameless and undefiled life made Him an appropriate guarantor or co-signer covering our imperfections. After establishing the need for a change of the priesthood, Paul describes the details as to how the new priesthood will administer the New Covenant, amplifying and bringing into stark reality what had been only seen in shadowy outline in the Old Covenant. The New Covenant is established on better promises, not law changes.