John Gill Commentary Hebrews 10:15

"And the Holy Spirit also beareth witness to us; for after he hath said," — Hebrews 10:15 (ASV)

Wherefore the Holy Ghost also is a witness to us
In (Jeremiah 31:33Jeremiah 31:34) . This preface to the following citation shows that the books of the Old Testament are of divine original and authority; that the penmen of them were inspired by the Holy Ghost; that he existed in the times of the Old Testament; that he is truly and properly God, the Lord, or Jehovah, that speaks in the following verses; and that he is a distinct divine Person, and the author of the covenant of grace; and in what he says in that covenant, he bears testimony to the truths before delivered, concerning the insufficiency and abolition of legal sacrifices, and of full and perfect remission of sin, by the blood and sacrifice of Christ:

for after that he had said before ;
what is expressed in the following verse.