God has spoken! – and speaks still, for his word is always living and active. But in the past he spoke in a piecemeal and partial way, whereas now he has spoken fully and finally – or, completely and climactically – in his Son. Jesus is God’s Last Word to us: not that he no longer speaks, but that he has nothing more to say. Completely and definitively he has said all he wants to say in Jesus. For in Jesus God is fully revealed (v.3a), and through Jesus redemption is fully accomplished (v.3b). God speaks not only to reveal himself, but to explain how we can know him; now that redemption is accomplished (hence Christ sits), revelation is complete.
These verses speak wonderfully of the majesty of Christ. Notice his relationship to creation: everything was made through him (v.2), everything was made for him (“heir of all things”), and everything is sustained by him (v.3). And notice his relationship to us: our Prophet, through whom God speaks, our Priest, who has offered the perfect sacrifice, and our King, reigning now at the right hand of God. Supremely, we are to notice his relationship to God: he is the Son, “the radiance of his glory and the exact representation of his being”. And an implication the writer wants us to grasp is that, in relation to angels, Jesus is utterly superior. The significance of that will become clear at 2:2, for the old covenant was mediated by angels, whereas the new covenant is mediated by Christ. His superiority to the angels establishes the superiority of the new covenant, God’s new and final word (cf 8:6).
I suspect there is unlikely to be time to dwell long on these verses, you may even decide to skip them out altogether, because to do them justice one should probably see the quotations in their Old Testament context. Better probably just to dwell on 1:1-4 and 2:1-4.
The first recipients of this letter it seems were Jewish Christians, who were tempted to drift back to Judaism – to ignore God’s Word to them in Christ, as though God’s Word to them in the Old Testament could suffice. So the writer shows how the Old Testament scriptures point to Christ’s far greater significance and glory. Again notice Christ’s unique relationship to the Father and to creation. He is the Ruler(vv.8, 13): angels are but servants (vv.7, 14).
Here’s the application. Because of who Jesus supreme glory, we must pay careful attention to all God says to us in him – ie we must pay attention to the Gospel. The danger for the for the original readers, as for us, is not so much that we might utterly reject it, but rather that we drift from it, through inattention. “Drift” speaks of a subtle danger, of which we might be scarcely aware. Verse 2 refers to the giving of Law at Mount Sinai, which it is implied in a few places in the Bible (eg Deut.33:2-4, Acts 7:53) Moses received from angels; but the Gospel message came to us from God’s Son, the Lord Himself, so all the more demands our attention. It speaks of a “great salvation”, and the letter is going to help us appreciate it more, but it will do us no good if we ignore it – indeed quite the reverse, the implication is that there will be even sterner punishment than that imposed under the old covenant. Though we may not have heard the message directly from Jesus, God has clearly authenticated (v.4) the apostles, through whom the message comes to us today.