N.T. Wright gives this simple explanation of Christ as the foundation of the priesthood of all believers in a sermon on Hebrews:
God chose the human race to be the priests of all creation, offering up creation’s worship to him and bringing his wise order to it. When humans sinned, God chose the nation of Israel to be the priests of the human race, offering up human praise and putting into operation God’s solution to the problem of sin. Israel herself, however, was sinful; God chose a family of priests (the sons of Aaron) to be priests to the nation of priests. The priests themselves failed in their task; God sent his own Son to be both priest and sacrifice. The inverted pyramid of priesthood gets narrower and narrower until it reaches one point, and the point is Jesus on the cross. The sacrifice of Jesus is the moment when the human race, in the person of a single man, offers itself fully to the creator.
– From his book, Following Jesus: Biblical Reflections on Discipleship
That’s really quite delicious. I meant to send you my paper on the institution of tabernacle worship as one of the links in this human-race-as-creation’s-priests chain Wright describes. I’ll do that soon, b/c I’d love to hear what you think.