God selects priests to be his holy representatives. Also, Jesus didn't really want to die, but god brought him to heaven because he was obedient and now he's in heaven and a priest of Melchisedec. They would like to explain this further, but the audience is really dumb, so progress is slow. They should be teachers by now, but they're only going over the basics. 'Paul' calls them babies, unable to distinguish right from wrong.
Now we're going to talk about perfection and the doctrine of baptisms, and of laying on of hands, and of
resurrection of the dead, and of eternal judgment (v. 2). Thrilling. Ex-christians can never come back to the fold because it's like nailing Jesus to that cross all over again. Also, they're hell-bound. Not this congregation, of course! There's still hope for them. So work hard and remember that even Abraham had kids eventually and you'll get into heaven, where Jesus is waiting.
Who is this Melchidesec that Hebrews is suddenly so enamoured with? Well, he's the king that met Abraham and blessed him after the slaughter of the kings way back in Genesis 14. Abraham gave him 10 percent of his war spoils. We know nothing else about this man, except that he's the reason you're supposed to pledge a tenth of your earnings to the church. According to 'Paul', the person who gives the blessing is better, as is the person who gets the tithes, because priests die, but Melchidesec is still out there, somewhere, like Godot. Also, if the Levite priests were so awesome, how come there's a new priestly order, hmm? And, here's the kicker: Jesus was from the tribe of Juda and he's also immortal. So there's a new priesthood, not based on blood, but on oath-taking and Jesus' priesthood is forever. And now barbecues, please, he's into promises, not sacrifices.
We need a new covenant, because if the first one had been perfect, we wouldn't need a new one. So soon god will wash away the dirty old covenant.