This triumphal song was probably occasioned by the same event as the forty-sixth [see on Psa 46:1, title]. The writer celebrates the glory of the Church, as the means of spiritual blessing to the nation. (Psa 87:1-7) His--that is, God's foundation--or, what He has founded, that is, Zion (Isa 14:32). is in the holy mountains--the location of Zion, in the wide sense, for the capital, or Jerusalem, being on several hills.