Among the first of ‘Christian’ books that I ever read (many moons ago now) was Denney’s The Death of Christ. I recall that one of the most significant impacts of that book on me concerned not only the awesome subject matter, but Denney’s theological method. [The same thing impressed me in Calvin and in Barth]. Here was a theologian doing rigorous exegesis. [What I didn’t know at the time was that Denney was principally a NT scholar].  Anyway, I revisited that book recently and was no less impressed by it. Here’s Denney’s comments on Hebrews 13:12:

There has been much discussion as to what sanctification in such passages means, and especially as to whether the word is to be taken in a religious or an ethical sense. Probably the distinction would not have been clear to the writer; but one thing is certain, it is not to be taken in the sense of Protestant theology. The people were sanctified, not when they were raised to moral perfection – a conception utterly strange to the New Testament as to the Old – but when, through the annulling of their sin by sacrifice, they had been constituted into a people of God, and in the person of their representative had access to His presence. The word ἁγιάζειν in short, in the Epistle to the Hebrews, corresponds as nearly as possible to the Pauline δικαιοῦν; the sanctification of the one writer is the justification of the other; and the προσαγωγή or access to God, which St. Paul emphasizes as the primary blessing of justification (Romans 5:2 and Ephesians 2:18, 3:12), appears everywhere in Hebrews as the primary religious act of drawing near, to God through the great High Priest (4:16, 7:19-25 and 10:22). It seems fair then to argue that the immediate effect of Christ’s death upon men is religious rather than ethical; in technical language, it alters their relation to God, or is conceived as doing so, rather than their character. Their character, too, alters eventually, but it is on the basis of that initial and primary religious change; the religious change is not a result of the moral one, nor an unreal abstraction from it.

– James Denney, The Death of Christ: Its Place and Interpretation in the New Testament (London: Hodder & Stoughton, 1909), 220-1.