The heavens have declared his righteousness Here he states that there would be such an illustrious display of the righteousness of God, that the heavens themselves would herald it. The meaning is not the same as in the beginning of the nineteenth psalm, "The heavens declare the glory of God," etc. In that psalm David means no more than that the wisdom and power of God are as conspicuous in the fabric of the heavens, as if God should assert them with an audible voice. The meaning of the passage before us is, that the spiritual righteousness of God should be so signally manifested under the reign of Christ as to fill both heaven and earth. There is much force in this personification, in which the heavens, as if even they were penetrated with a sense of the righteousness of God, are represented as speaking of it. It is equally probable, however, that the heavens signify here the angels, who are contained in heaven, by the figure of metonomy or synecdoche, while, in the corresponding clause, instead of the earth being mentioned, he speaks of the peoples who dwell upon it. The angels may very properly be said to announce and celebrate the Divine glory.

The heavens declare his righteousness - See the notes at Psalm 50:6. Compare the notes at Psalm 19:1.
And all the people see his glory - As manifested in the heavens, and in the power which he puts forth on the earth. That is, (they have the opportunity of seeing it; it is made manifest in all his works. They see what in fact is a manifestation of his glory, to wit, his great and wondrous works. It is not affirmed that they "appreciate" all this, or that they see this to be a manifestation of his glory - which would not be true - but that they see what is in fact a revelation of his greatness, his wisdom, and his power.

The heavens declare his righteousness - They also, in this poetic description, become intelligent beings, and proclaim the majesty and the mercy of the Most High. Metaphorically, they may be said to declare his glory. Their magnitude, number, revolutions, order, influence, and harmony, proclaim the wondrous skill, matchless wisdom, and unlimited power of the Sovereign of the universe. See the notes on Psalm 19:1-14 (note).
And all the people see his glory - Whatsoever God has made proclaims his eternal power and Godhead; and who, from a contemplation of the work of his hands, can be ignorant of his being and providence?

The heavens declare his righteousness,.... His justice in punishing his enemies; the lightning and the thunder in the heavens, the tokens of his wrath, and instruments of it; his wrath itself, which is revealed from heaven, Romans 1:18, or the inhabitants of heaven, as Aben Ezra; the angels of heaven; so the Targum, "the angels on high (or of heaven, as in the king's Bible) declare his righteousness"; see Revelation 16:5, it is true of the ministers of the Gospel, who are Christ's angels or messengers, men of heavenly gifts and grace, whose work it is to declare the justifying righteousness of Christ, which is revealed in the Gospel from faith to faith, and which is therefore called the word of righteousness, and the ministration of it, Romans 1:17,
and all the people see his glory; the glory of his justice in the destruction of his enemies; the glory of his power and grace in the salvation of his chosen; the glory of God in the face of Christ; the glory of Christ himself, as the only begotten of the Father; the glory of his person, office, grace, and righteousness, in the glass of the Gospel; the glory and honour he is now crowned with in heaven; and all the people, even all the chosen, redeemed, and called people, shall behold his glory to all eternity: it seems chiefly to respect the revelation of his glory, and his people's view of it at his first coming; see Isaiah 60:5.

heavens--or, their inhabitants (Psalm 50:6), as opposed to "nations" in the latter clause (compare Isaiah 40:5; Isaiah 66:18).

Heavens - The angels, yea God himself from heaven.