Hebrews 10:7

Verse 7. Then said I. I the Messiah. Paul applies this directly to Christ, showing that he regarded the passage in the Psalm as referring to him as the speaker. Lo, I come. Come into the world, Heb 10:6. It is not easy to see how this could be applied to David in any circumstance of his life. There was no situation in which he could say that, since sacrifices and offerings were not what was demanded, he came to do the will of God in the place or stead of them.