The Letter to the Hebrews is addressed to Jewish Christians and is, therefore, thematically much closer to the Gospels and the early part of Acts, which is why I want to look at it before we come to Paul. The argument is by no means an easy one, so if you’re not interested in the sordid details of the exposition that follows, here is the executive summary:
Jesus’ death was a once-and-for-all sacrifice for the sins committed by Israel under the Law. Just as his death on a tree redeemed Jews from the curse of the Law, so Jesus’ offering of his own blood, by which he qualified to enter the heavenly sanctuary, gained for Jews forgiveness of sins committed under the Law and made possible a new sacrifice-free covenant.
This lends further weight to my cautious thesis regarding the central atonement narrative, which is that Jesus died directly for the sins of Israel, as an outworking of the Law, and only indirectly for the sins of Gentiles.