I will set his hand over the sea,
    his right hand over the rivers.
²⁶ He will call out to me, ‘You are my Father,
    my God, the Rock my Savior.’
²⁷ And I will appoint him to be my firstborn,
    the most exalted of the kings of the earth.
²⁸ I will maintain my love to him forever,
    and my covenant with him will never fail.
²⁹ I will establish his line forever,
    his throne as long as the heavens endure. Psalm 89:25-29

OK so verse 25 does not sound like He is talking about King David anymore. Who do you think God is talking about here?