Hebrews is centered around the theme of the supremacy and the primacy of Christ. Jesus is the best. If you were going to sum up Hebrews in one sentence, that is what it would be. The author of Hebrews is unknown but, he's writing to a group of believers who have trusted in Jesus Christ and they are coming out of a Jewish background. So they've been involved in synagogue life, they've been involved in temple worship, offering sacrifices of animals. They've been submitted under the Levitical priesthood; they've been hearing the Torah, the five books of Moses, they have been learning from the law and the prophets. That's their background and their history and they are coming out of that and they have believed in Jesus Christ. They haven't completely abandoned the Old Testament, of course, because it is still Scripture, but they have moved on and they have come to a saving faith in Jesus but they are tempted to go back to what they used to do. They are tempted to move themselves back to a faith that is not a faith alone, in Jesus Christ alone, by grace alone, through the word of God alone. They are tempted to add back in the law and the prophets and submitting ourselves to the sacrificial system and the priests of that day. Another way it could be said is that Jesus is better. He is better than angels. He is the prophet who far outshines all of the Old Testament prophets. He is better than Moses. And the laying down of his life as the ultimate one-time sacrifice is better than all of the sacrifices in the entire sacrificial system that was laid out for and practiced by the Levitical priesthood. The writer of Hebrews is telling people, "Don't go back. Jesus is better."