In Hebrews 2:4, God bore witness with signs and gifts of the Holy Spirit, directly tying to the Holy Spirit's witness.

In Hebrews 3:7, the Holy Spirit speaks, paralleling the Spirit's testimony in the main verse.

In Hebrews 9:8, the Holy Spirit indicates the way into the Holiest was not yet open, similar to the Spirit's witness.

In 2 Samuel 23:2, David says the Spirit spoke through him — the same divine agency behind the Jeremiah quotation in Hebrews 10:15.

Nehemiah 9:30 recounts God testifying through His Spirit by the prophets — exactly the pattern Hebrews 10:15 uses to introduce the Jeremiah quote.

Acts 28:25 quotes Paul attributing Isaiah’s prophecy to the Holy Spirit — the same interpretive move Hebrews 10:15 makes with Jeremiah.

1 Peter 1:11 says the Spirit of Christ testified beforehand through prophets — directly parallel to the Spirit witnessing in Hebrews 10:15.

2 Peter 1:21 states prophets spoke as moved by the Holy Spirit — the foundational claim behind Hebrews 10:15’s appeal to the Spirit’s words.

Revelation 19:10 identifies the testimony of Jesus as the spirit of prophecy, connecting to the Spirit's testifying in Hebrews 10:15.

John 14:26 describes the Spirit teaching and reminding, complementing the Spirit's testimony in Hebrews 10:15 about the new covenant.

John 15:26 describes the Spirit testifying of Christ — a different aspect of the Spirit’s witness, but both involve the Spirit as testifier.