And as Jesus taught in the temple, he said, “How can the scribes say that the Christ is the son of David? David himself, in the Holy Spirit, declared, “ ‘The Lord said to my Lord, “Sit at my right hand, until I put your enemies under your feet.” ’” (Mark 12:35–36, ESV)

Jesus does a remarkable thing here and we must not miss it.  He refers to a verse in the Tanakh [the Jewish Scriptures also known as the Old Testament to us] which David himself wrote, Psalm 110.1. Jesus points out that David wrote “in the Holy Spirit.”  This is amazing.  David was writing his own words and forming them into his own sentences, but Jesus says he wrote “in the Holy Spirit.”

Notice also that Jesus’ opponents do not disagree wit him.  Both sides of this debate believed that when David wrote something, he wrote in the power of the Holy Spirit, which is why an appeal to the Scriptures is a final appeal.  The Scriptures were the ultimate authority.

This passage is very important in driving our understanding of the doctrine of the inspiration of the Scriptures.  If David wrote “in the Holy Spirit,” then the other authors of the Tanakh also wrote “in the Holy Spirit.”  It’s easy to understand then, how the New Testament church would come to understand that, since the New Testament writers were also writing “Scripture,” then they would have been writing “in the Holy Spirit.”  As Peter will write:

And count the patience of our Lord as salvation, just as our beloved brother Paul also wrote to you according to the wisdom given him, as he does in all his letters when he speaks in them of these matters. There are some things in them that are hard to understand, which the ignorant and unstable twist to their own destruction, as they do the other Scriptures.” (2 Peter 3:15–16, ESV)

John Stott, while addressing this issue wrote something to the effect of, “we bow to the authority of Scripture, because we bow to the authority of Christ, and we find Christ in the gospels bowing to the authority of Scripture.”