Psalm 110:1-4:

The rod of your strength Jehovah will send out of Zion, saying: ‘Go subduing in the midst of your enemies.’

19. The one prophesied to wield the rod of strength on Mount Zion had to be whose descendant, and why was David not prophesying about kings from Solomon to Zedekiah?

¹⁹ Note what those inspired words signify. The fact that King David said that Jehovah would send out the King’s rod of strength from Zion indicates that the King would be a fleshly descendant of David. According to Jehovah’s covenant with David for an everlasting kingdom, no one would sit as king on Mount Zion and wield the rodlike scepter of strength except a fleshly descendant of David. (2 Samuel 7:8-16) Hence, this one whose rod of strength would be sent out of Zion would be called a “son of David.”

Although David sat on the “throne of Jehovah” on earthly Mount Zion, he never, even at his death, ascended to heaven and sat down on the “right hand” of Jehovah. But the one who would become David’s “Lord” would do so. His royal position at Jehovah’s right hand in heaven could be referred to as a heavenly Mount Zion because it was pictured by the earthly Mount Zion, which used to be enclosed within Jerusalem’s walls but is not so today.