The Old Testament had much to say about the presence of God. Throughout the history of Israel, God’s presence was mediated through fire (Exod 3:6; Deut 5:4), through blazing light (Exod 33:18–23), through visions (Ezek 1:28) and angels (Jdg 6:21–22; cf. 13:21–22), through the temple worship (Pss 27:4; 63:1–2), and even through God’s own Word (1 Sam 3:21). But with the coming of Jesus and the New Covenant era, the glory of God’s presence is now uniquely and supremely manifested “in the face of Christ” (2 Cor 4:6). This makes sense, of course, because Christ is the perfect “image of God” (2 Cor 4:4).
This is precisely the testimony of the opening verses of the Book of Hebrews. Though God had revealed Himself by speaking to the fathers in the prophets in many portions and in many ways, in these last days He has spoken finally and decisively in His Son (Heb 1:1). Christ is therefore the radiance of the Father’s glory (1:3)—the manifestation of the very presence of God, the “effulgence of the divine glory,” as one commentator colorfully puts it.