How do we know Christ's priesthood is superior to the Aaronic priesthood?

Hebrews 7:11 points out that if perfection could have been achieved through the Levitical priesthood, there would be no need for another priest to arise after the order of Melchizedek. This indicates that the priesthood of Christ is fundamentally different and superior to that of the Aaronic priests. While the Aaronic priests were from the tribe of Levi and had to offer sacrifices for their own sins, Christ, being the eternal Son of God, offers a sinless sacrifice as both Priest and Lamb. His priesthood is forever, as He abides in the presence of God, interceding for His people.