"As the only full-length sermon recorded in the New Testament, Hebrews gives us special insight into the nature of early Christian preaching and its theological character according to Scripture. By its shape and character the Hebrews sermon highlights the fact that preaching (at least for this NT writer) consisted fundamentally in proclaiming Christ through the exposition of Scripture and exhorting hearers to respond. The writer clearly believes that his proclamation of Christ from Scripture is rightly viewed as a 'word' from God (4:13; 5:11; 13:22). We might think that such a high view of the discourse rightly pertains only to this writer, given that his discourse was accepted within the canon of New Testament Scripture. He, however, views the function of 'speaking the word of God' as something that is characteristic of church leaders generally, rather than of him uniquely (13:7).
For the writer of Hebrews, the word of God is supremely expressed in the person of the Son, so it is no surprise that he moves seamlessly from proclaiming the word of God to inviting his hearers to approach the presence of God through Christ. There is a real sense that the proclamation of the word of God facilitates a personal encounter with God. When preaching is set in this light, it is natural that the writer should present his preaching as an event carrying judicial implications. As hearers of God's word encounter God (who is both Judge and Saviour) through his word, they must respond rightly in faith or face the danger of losing out on salvation. At the same time, however, this proclaimed word offers access to the heavenly rest of God. The context in view for the Hebrews sermon is the gathering of God's people. This point is not merely a matter of practicality, nor is it theologically incidental; rather, the proclamation of the word of God to the assembly of God's people is the special means by which God's people hear God address them from heaven. And as the gathered people of God listen to God's word in scattered locations throughout the world, they mirror -- in a limited but profound way -- the heavenly assembly of which they are a part." (Griffiths, Jonathan. Preaching in the New Testament: An exegetical and biblical-theological study, NSBT, 117.)