John Calvin Commentary Psalms 97:6

"The heavens declare his righteousness, And all the peoples have seen his glory." — Psalms 97:6 (ASV)

The heavens have declared his righteousness. Here, the psalmist states that there will be such an illustrious display of God's righteousness that the heavens themselves will herald it. The meaning is not the same as in the beginning of Psalm 19: The heavens declare the glory of God, and so on (Psalms 19:1).

In Psalm 19, David simply means that God's wisdom and power are as evident in the structure of the heavens as if God were to declare them with an audible voice. The meaning of the present passage, however, is that God's spiritual righteousness will be so remarkably manifested under the reign of Christ that it will fill both heaven and earth.

This personification carries great force: the heavens, as if even they were imbued with an awareness of God's righteousness, are depicted as speaking of it. It is equally probable, however, that by "the heavens" the psalmist here means the angels, who are contained in heaven, using a figure of metonymy or synecdoche. This interpretation is supported because, in the corresponding clause, instead of mentioning the earth, the psalmist speaks of the peoples who live on it. The angels can very properly be said to announce and celebrate the Divine glory.