The work they do as priests is really only a copy and a shadow of what is in heaven. It is the same as it was with Moses. When he was about to build the Sacred Tent, God told him, "Be sure to make everything according to the pattern you were shown on the mountain."
But now, Jesus has been given priestly work which is superior to theirs, just as the covenant which he arranged between God and his people is a better one, because it is based on promises of better things.
But God finds fault with his people when he says, "The days are coming, says the Lord, when I will draw up a new covenant with the people of Israel and with the people of Judah.
It will not be like the covenant that I made with their ancestors on the day I took them by the hand and led them out of Egypt. They were not faithful to the covenant I made with them, and so I paid no attention to them.
Now, this is the covenant that I will make with the people of Israel in the days to come, says the Lord: I will put my laws in their minds and write them on their hearts. I will be their God, and they will be my people.