New Defender's Study Bible Notes
3:7 Holy Ghost saith. Psalm 95:7-11 is under discussion in the section from Hebrews 3:7–4:10, with the author (possibly Paul) drawing an analogy between the rebellious Israelites in the wilderness under Moses and the professing Jewish believers of his own day, who were being tempted back into Jewish legalism. Specifically he is quoting this passage here (Hebrews 3:7-11) as an assertion of the Holy Spirit Himself. In Hebrews 4:7, he indicates that the author of the words was David, even though Psalm 95 carries no superscript of authorship (the same situation occurs when Psalm 2:1-2 is quoted in Acts 4:25-26 as written by David). It is thus a significant characteristic of divine inspiration that a section of Scripture is attributed both to David and the Holy Spirit, even when the section seems officially anonymous.