“The heavens declare the glory of God, and the sky above proclaims his handiwork.” (Psalm 19:1, ESV)
David personifies nature here [as the writers of Scripture so often do]. He has the heavens speaking and the sky proclaiming. We don’t often think of nature this way, but the Hebrew culture seemed to be saturated with this notion that nature proclaimed a message and if we would study nature and embrace nature and be absorbed in nature we would hear that message.
The message that the heavens declare: God is great. Simple. Straightforward. Elegant. God. Is. Great.
I have seen no better working out of that truth in nature than this excellent video by Louie Giglio:
“Praise him, sun and moon, praise him, all you shining stars! Praise him, you highest heavens, and you waters above the heavens!” (Psalm 148:3–4, ESV)