Hebrews uses the language of “witness” in three significant ways, each related to Scripture. First, God testifies to the person and work of his Son through Moses in the law (Heb 3:5; 8:5; 10:1). God also testifies to his Son and the establishment of the new covenant through the prophets and psalmists (7:8, 17; 10:15). So the writer of Hebrews uses these biblical testimonies as the basis for his own testimony to Christ.
Second, God testifies to different dimensions of faith in the record concerning famous biblical characters (Heb 11:2, 4, 5, 39). In Hebrews 11, the writer identifies worship, perseverance, obedience, testing, sanctification, and hope, as indications of genuine faith, or as the expected outcomes of faith. However, although believers in both testaments share similar circumstances and are called to make similar responses, the writer concludes by emphasizing a significant difference (11:39). Old Testament believers saw the fulfilment of particular promises in this life (e.g., 6:15; 11:11, 33), but none of them experienced the comprehensive blessings of the messianic era. None of them were “perfected” in the way that Christ has “perfected” us (7:19; 10:1, 14; though see 12:23).
Third, with this qualification made, the writer confirms that these biblical characters testify to Christian believers about the realities of faith (12:1). As those who have God’s testimony to their faith recorded in Scripture, they now “surround” Christian believers and become a source of encouragement to “throw off everything that hinders and the sin that so easily entangles,” so as to “run with perseverance the race marked out for us” (NIV). But there is a further testimony to faith for those who fix their eyes on Jesus, “the pioneer and perfecter of faith” (12:2). The suffering and exalted Lord Jesus is the supreme witness to persevering faith (12:3–4). As such, he is also the source of ultimate encouragement and hope for disciples who struggle against opposition and sin (12:4–17). By his high-priestly work, he is able to “save completely those who come to God through him” (7:25).
Although Hebrews does not use the language of witness with reference to Christians, it is easy to see how this theme might be developed. We are to “imitate those who through faith and patience inherit what has been promised” (6:12; 13:7). We are to listen to the exhortations of Scripture and “endure hardship as discipline” (12:5–7), trusting in God’s fatherly care, and understanding his good purpose in allowing his children to suffer in various ways (12:7–11). Learning to support and strengthen one another in such circumstances (12:12–13; cf. 13:1–3), we may testify to the distinctive character and sustaining power of Christ-directed and Christ-empowered faith. A verbal dimension to this witness may be implied by a reference to Jesus as “the apostle and high priest of our confession” (3:1 ESV, HCSB; cf. 4:14; 10:23; 13:15).