My favourite book in the entire Bible is that of Hebrews. I am currently re-reading it as part of my daily Scripture reading at the moment. What is interesting is that even über liberal commentators on the New Testament admit that it is an early (pre-70) composition. Richard Carrier wrote the following in defence of the view that Hebrews pre-dates the destruction of the Second Temple:
The overall argument of this letter is that Jewish Christians should not backslide now, because Judaism can no longer guarantee their salvation (this letter does not advocate Torah-observant Christianity: e.g., Heb. 13.9). That the temple cult no longer existed (and God did nothing to save the Jews from destruction, not even as a nation, but neither to save his temple and the cult being paid to him there) would have been so extremely effective and important an argument in this context that for the author never once to use it is all but impossible—unless Hebrews was written before the year 70, before even the year 66 (when the Jewish War started, since that fact alone could hardly escape mention). For example (and this is just one example among many), in Heb. 10.1-4 it is clearly assumed the temple sacrifices are still being performed: because the author makes an argument against their effectiveness, yet the obvious argument—that they aren’t even being performed any more and therefore can’t be effective even if ever they were—doesn’t occur to him. He even asks as a rhetorical question if the effects of these sacrifices lasted longer than a year, ‘would they not have ceased to be offered [by now]?’ (10.3). It’s undeniably clear the author has no idea here that they had ceased. We must conclude, then, that they had not. I find this so decisive a point that maintaining a later date for Hebrews is simply not tenable. I know of no logically valid argument for that. (Richard Carrier, On the Historicity of Jesus: Why We Might Have Reason to Doubt [Sheffield: Sheffield Phoenix Press, 2014], 539-40. Emphasis in original)
This is significant as Hebrews presents a very high Christology (e.g., 1:2, 10-12 affirms Christ’s personal pre-existence and role in the Genesis creation), showing that such is not a much later development within early Christianity.