NOTES for Heb 12:18-29
Speaking about the history of the covenant, the author of the letter uses the traditional Jewish correlation of the revelation received at Sinai, where the first covenant with God in the history of the Jewish people was concluded, with the messianic revelation traditionally connected with Zion and with the promises given to David (vv. 18-24). At the same time, not surprisingly, he speaks of the promises given by God as promises already fulfilled, having in view above all the heavenly Jerusalem mentioned in the book of Isaiah (vv. 22-24; cf. Isa. 60). In this way the author of the letter brings new shades of meaning into the traditional idea: for him the comparison of Sinai with Zion becomes a comparison of the old, Sinaitic covenant with the new, messianic covenant. And for him the messianic covenant is obviously inseparable from the Kingdom, whose triumph he already sees not in the future but in the present (vv. 25-29).
Apparently, for many of his contemporaries and fellow believers, the catastrophe of A.D. 70 became a sign that the triumph of the Kingdom was being postponed, and postponed for a long time, that some failure had occurred in the fulfillment of God's plans, so that now, for a time, the Kingdom and all the plans, hopes, and works connected with it could, if not be forgotten, then at least be postponed indefinitely. But the author of the letter, remaining a faithful disciple of the apostle Paul, emphasizes that God's plan is being carried out in its own course, that the catastrophe of A.D. 70 does not mean God has abandoned all His designs, and that the Kingdom is still just as near as in the days of the Savior's earthly ministry, when He Himself bore witness to its nearness.
At first glance all this seems self-evident, at least self-evident for a Christian, but after the shock experienced in A.D. 70 by both the Synagogue and the Church, even the most obvious things ceased for a time to seem obvious. And the author of the letter never tires of reminding his readers of the main thing that forms the foundation of Christian life: the Kingdom, whose history continues despite any disasters, even the most terrible, that happen in our world, a world being transfigured but not yet transfigured, and therefore not free from evil.