(19) At one time you spoke in a vision to your holy one and said, “I have bestowed help on one who is mighty. I have exalted a young man from among the people. (20) I have found David, my servant. With my holy oil I have anointed him (21) so that my hand will be established with him. Also my arm will strengthen him. (22) The enemy will not subject him to tribute. The son of wickedness will not afflict him. (23) I will crush his foes before him and strike down those who hate him. (24) My faithfulness and my steadfast love (will be) with him, and in my name will his horn be exalted. (25) I will set his hand over the sea and his right hand over the rivers. (26) He will call to me, ‘You (are) my father, my God, and the rock of my salvation.’ (27) I will appoint him my firstborn, the highest of the kings of the earth. (28) My steadfast love will keep him forever, and my covenant will be confirmed for him. (29) I will establish his offspring forever and his throne as the days of the heavens.”
This entire segment consists of Yahweh's verbal testimony regarding David. Several terms found here are repetitions from earlier verses in the psalm. “Hand” and “arm” recur (cf. vss. 13 & 21) with “hand” used twice (vs. 25). “Faithfulness” and “steadfast love” are also used again (cf. vss. 24 & 28 with vss. 1, 2, & 14). Two other terms, “my name” and “horn exalted,” are found again (cf. vs. 24 with vss. 12 & 17). God promises to David both an offspring and a throne forever (vs. 29 reminding us of vs. 4). One other word is given special emphasis: “forever” found twice (vss. 28 & 29).
I. Elected as king: Yahweh choosing David (19-21)
II. Established as king: Yahweh enthroning David (22-27)
III. Eternally the king: the Davidic Covenant (28 & 29)
God exalted David by choosing him, establishing his rule, and making an eternal covenant with him.
The phrase, “I will appoint him my firstborn” (vs. 27), may be unfamiliar to those who no not know the language of royal succession. As an example, in England the next in line to the throne after Queen Elizabeth abdicates or dies should be Prince Charles, her oldest son. As the firstborn, he is heir to the throne and will eventually become king unless something unforeseen should happen.
Although the eighth born son in his earthly family, David was appointed God’s firstborn and designated king over Israel three thousand years ago. The Messiah, David’s Son, holds that same title: “God’s firstborn, his only begotten Son.” Although “firstborn” normally refers to the child who opens the womb, in this usage it signifies a position of preeminence given to the one God appointed as his earthly ruler. The promises given to the original David in Psalm 89 also belong to the offspring of David, the Messiah, who will rule eternally.