Blessed is the nation - For the meaning of the word “blessed,” see the notes at Psalms 1:1. The idea here is, that the nation referred to is happy, or that its condition is desirable. What is true of a nation is also as true of an individual.
Whose God is the Lord - Whose God is Yahweh - for so this is in the original Hebrew. That is, the nation which worships Yahweh, and is under his protection. This is evidently said to distinguish such a nation from those which worshipped false gods or idols. Such a nation is blessed or happy, because:
(a) He is a real God, the true God, and not an imagination or fiction;
(b) because His laws are just and good, and their observance will always tend to promote the public welfare and prosperity;
(c) because His protection will be vouchsafed to such a nation; and
(d) because His worship, and the influence of His religion, will tend to diffuse virtue, intelligence, purity, and truth, over a land, and thus will promote its welfare.
And the people whom he hath chosen for his own inheritance - Chosen to be “His;” or, His portion. The primary reference here is undoubtedly to the Hebrew people, called his “inheritance:” Deuteronomy 4:20; Deuteronomy 9:26; Deuteronomy 32:9; Psalms 74:2; Psalms 78:62, Psalms 78:71; or “heritage,” Psalms 94:5; Jeremiah 12:7, Jeremiah 12:9; but what is here affirmed of that people is true also of all other people who worship the true God.