Paul seems to be arguing that the blessings promised to David have been given to Jesus Christ, and that we can be sure of this because he was resurrected from the dead. David was promised that a king, whose kingdom would never end (2 Samuel 7:13), would come from his line. Since Jesus Christ has been resurrected, he is the one who receives this promised blessing. The holy and sure blessings belong to the holy descendant of David and through him they are shared with all of God’s people (believers in Christ).1
34 And as for the fact that he raised him from the dead, no more to return to corruption, he has spoken in this way, “‘I will give you the holy and sure blessings of David.’