Great is the Lord - That is, he is high and exalted; he is a Being of great power and glory. He is not weak and feeble, like the idols worshipped by other nations. He is able to defend his people; he has shown his great power in overthrowing the mighty forces that were gathered together against the city where he dwells.
And greatly to be praised - Worthy to be praised. In his own nature, he is worthy of adoration; in interposing to save the city from its foes, he has shown that he is worthy of exalted praise.
In the city of our God - Jerusalem. In the city which he has chosen for his abode, and where his worship is celebrated. See the notes at Psalms 46:4. This praise was especially appropriate there:
(a) because it was a place set apart for his worship;
(b) because he had now interposed to save it from threatened ruin.
In the mountain of his holiness - His holy mountain; either Mount Zion, if the psalm was composed before the building of the temple - or more probably here Mount Moriah, on which the temple was reared. The names Zion, and Mount Zion, however, were sometimes given to the entire city. Compare the notes at Isaiah 2:2-3.