Charles H. Spurgeon on Psalms 72:8

He shall have dominion also from sea to sea. Wide spread shall be the rule of Messiah; only the Land's End shall end his territory: to the Ultima Thule shall his sceptre be extended. From Pacific to Atlantic, and from Atlantic to Pacific, he shall be Lord, and the oceans which surround each pole shall be beneath his sway. All other power shall be subordinate to his; no rival nor antagonist shall he know. Men speak of the Emperor of all the Russias, but Jesus shall be Ruler of all mankind. And from the river unto the ends of the earth. Start where you will, by any river you choose, and Messiah's kingdom shall reach on to the utmost bounds of the round world. As Solomon's realm embraced all the land of promise, and left no unconquered margin; so shall the Son of David rule all lands given him in the better covenant, and leave no nation to pine beneath the tyranny of the prince of darkness. We are encouraged by such a passage as this to look for the Saviour's universal reign; whether before or after his personal advent we leave for the discussion of others. In this Psalm, at least, we see a personal monarch, and he is the central figure, the focus of all the glory; not his servant, but himself do we see possessing the dominion and dispensing the government. Personal pronouns referring to our great King are constantly occurring in this Psalm; he has dominion kings fall down before him, and serve him; for he delivers, he spares, he saves, he lives, and daily is he praised.