*Minor differences ignored. Grouped by changes, with first version listed as example.
O give thanks unto the God of heaven - The God who reigns in heaven; whose home is heaven.
For his mercy - In view of all this - of all that he does in heaven and on earth - let praise be ascribed to him. To know the measure of the praise due to him; to see how great is his "mercy," it would be necessary to know all that he does in heaven and on earth. That will not be known here. It will constitute the theme of contemplation and praise forever and ever. Enough, however, is known here to show the propriety of repeating again, again, and again, as in this psalm, the language, "For his mercy endureth forever;" "For his mercy endureth forever;" "For his mercy endureth forever."
(i) O give thanks unto the God of heaven: for his mercy [endureth] for ever.
(i) Seeing that all ages have had most plain testimonies of God's benefits.
O give thanks unto the God of heaven,.... the Maker of it, in which the glory of his wisdom and power is displayed; the possessor of it, where he dwells, has his throne, and keeps his court; from whence all blessings, temporal and spiritual, come and where he has prepared glory and happiness for his people hereafter, a house eternal in the heavens, an inheritance reserved there, a better and a more enduring substance;
for his mercy endureth for ever; for though the above character is expressive of his sovereignty and dominion, yet he exercises it in a way of grace and mercy to the sons of men; and therefore they have reason to give thanks unto him and praise him for his kindness and favours shown to them on earth.
God of heaven--occurs but once (Jonah 1:9) before the captivity. It is used by the later writers as specially distinguishing God from idols.
*More commentary available at chapter level.