Wherefore Thou art great. Figure of speech Metonymy (of Subject), App-6, wherefore. will declare and praise Thee as great.
O LORD God. O Jehovah Elohim. Note the change, because it is not now in connection with the earth, but what He is in Himself.
Related Commentaries of 2 Samuel 7:22
2 Samuel 7:22
22 Wherefore thou art great, O LORD God: for there is none like thee, neither is there any God beside thee, according to all that we have heard with our ears.