“David.” This is the figure of speech antonomasia, “name change,” where a person is called by a name other than his or her own name in order to import characteristics from the other person. Here the Messiah is called “David” to highlight that the Messiah would be a lineal descendant of David, which he was through Mary, and also because the reign of David, especially early on, was a glorious time in Israel and the Messiah’s reign on earth will be a glorious time. The Messiah is called “David” in Ezekiel 34:23, 24, and 37:24, 25. We also see antonomasia when John the Baptist is called “Elijah” (Mal. 4:5), and Jehu is called “Zimri” (2 Kings 9:31). [For more on antonomasia, see commentary on Matthew 17:10. For more on Jesus’ kingdom on earth, see Appendix 3, Christ’s Future Kingdom on Earth].
“king.” Here the Messiah is called the “king,” while in other places he is called the “prince” (cp. Ezek. 34:24). While Jesus Christ is a “prince” under his father, God, he will be the de facto king over the people, ruling with God’s authority.