Does this mean that the law is against God’s promises? Never! That would be true only if the law could make us right with God. But God did not give a law that can bring life.
The people were given the law concerning the system of priests from the tribe of Levi, but they could not be made perfect through that system. So there was a need for another priest to come, a priest like Melchizedek, not Aaron.
But the priestly work that has been given to Jesus is much greater than the work that was given to the other priests. In the same way, the new agreement that Jesus brought from God to his people is much greater than the old one. And the new agreement is based on promises of better things.