These earthly entities should praise Yahweh because He is greater than anything in heaven and on earth. Only His name is worthy of exaltation. In particular, God had raised up a king (strong one, horn) for His chosen people Israel. This person had become the praise of all His saints in Israel, the nation close to His heart. [source][source][source]
"Thus far the psalmist has not said anything about the people of God. He has made reference to the "angels" of God ( Psalm 148:2) in heaven but has left out any reference to the people who do his bidding on earth until the very end. This is a climactic development of the psalm. God loves and cares for all his creation, but he has a special affinity for "his people," "his saints" ..., "Israel," also known as "the people close to his heart" ..." [1][source]
The whole creation should praise God because He is the Creator and Sustainer of all. Furthermore, He blessed Israel by giving His chosen people worthy leadership. The "horn" God raised up-who is worthy of all praise, i.e, all forms of genuine praise, the sum total of all collective praises, and praise from all created things, living and inanimate-is Jesus Christ, the descendant of David. [source][source][source]