The creatures placed in the upper world called on to praise the Lord. (1-6) Also the creatures of this lower world, especially his own people. (7-14)
@Verses 1-6 We, in this dark and sinful world, know little of the heavenly world of light. But we know that there is above us a world of blessed angels. They are always praising God, therefore the psalmist shows his desire that God may be praised in the best manner; also we show that we have communion with spirits above, who are still praising him. The heavens, with all contained in them, declare the glory of God. They call on us, that both by word and deed, we glorify with them the Creator and Redeemer of the universe.
@Verses 7-14 Even in this world, dark and bad as it is, God is praised. The powers of nature, be they ever so strong, so stormy, do what God appoints them, and no more. Those that rebel against God's word, show themselves to be more violent than even the stormy winds, yet they fulfil it. View the surface of the earth, mountains and all hills; from the barren tops of some, and the fruitful tops of others, we may fetch matter for praise. And assuredly creatures which have the powers of reason, ought to employ themselves in praising God. Let all manner of persons praise God. Those of every rank, high and low. Let us show that we are his saints by praising his name continually. He is not only our Creator, but our Redeemer; who made us a people near unto him. We may by "the Horn of his people" understand Christ, whom God has exalted to be a Prince and a Saviour, who is indeed the defence and the praise of all his saints, and will be so for ever. In redemption, that unspeakable glory is displayed, which forms the source of all our hopes and joys. May the Lord pardon us, and teach our hearts to love him more and praise him better.