The original audience of Hebrews were Christians who had in the past been persecuted, though not to the point of suffering martyrdom according to Hebrews 10, but more recently the pressure had come off somewhat, and they were in danger of drifting away from their first allegiance to the Lord Jesus. But they were drifting away apparently in a particular direction. They weren't drifting away toward secularism. They weren't drifting away towards contemporary pagan philosophy or the like. They seemed to be drifting away toward more allegiance to some sort of Old Testament styled theology than to the Lord Jesus. In other words, it sounded as if they were drifting towards being Old Testament believers after the new covenant had already dawned, and that meant that they were focusing attention on the very Old Testament things that point to Jesus instead of the Jesus to whom Old Testament things pointed. And we can infer the reasons for that, but they're only inferences. It may well be, though it's not certain, it may well be that they were converted Jews who wanted so to remain within the realm of social acceptability to their fellow Jews that they were downplaying the uniqueness of Jesus and trying to show how kosher they continued to be, and how continually in line with Jewish habits and traditions and theology and so on. So, their particular form of drift seems to be toward a kind of Old Testament view of God and worship and sacrifice and so forth, rather than seeing how Jesus is the consummation and fulfillment of all of these trajectories in the Old Testament that point forward to and are fulfilled in him.