Psalm 19 sets two kinds of speech side by side and shows that they say the same thing. First comes the sky: 1"The heavens declare the glory of God." It speaks without words. 3"There is no speech, nor are there words, whose voice is not heard," and yet 4"their voice goes out through all the earth." Every nation under that sky can hear it, whether or not anyone listens. Nobody has to learn a language to be addressed by the stars.
The sun gets a tent of its own and 5"runs its course with joy" like a strong man. David lets the sun run a course as a creature. Then one line closes the section: 6"there is nothing hidden from its heat." The sun reaches every shaded place.
At verse 7 the psalm turns without warning to another kind of speech. In the first half God is called by the general word for God. In the second half, the covenant name LORD appears six times in three verses. Creation can tell any nation that a Maker exists, one powerful enough to hang a sun in the sky. Only the LORD's own word says who he is and what he wants.
The law, testimony, precepts, and commandment each come with a quality and an effect: perfect, reviving the soul; sure, making wise the simple; right, rejoicing the heart; pure, enlightening the eyes. Sunlight can expose a hidden thing. It cannot revive a soul or make a simple heart wise.
The word "hidden" in verse 6 shares a Hebrew root with the "hidden faults" of verse 12. David has felt the sun search every shaded place, and he feels the law doing the same to him. 12"Who can discern his errors? Declare me innocent from hidden faults." Wonder turns to exposure, and exposure turns to prayer. He asks to be kept back from 13"presumptuous sins," the ones we see clearly and excuse anyway. Yet he still describes God's word as 10"more to be desired" than fine gold, and sweeter than honey. A man who has been searched by the light still wants it, and that is the surest sign the light was good for him.
The psalm ends with one of the most prayed lines in the Psalter: 14"Let the words of my mouth and the meditation of my heart be acceptable in your sight, O LORD, my rock and my redeemer." The word behind "acceptable" is used of offerings that please God. David is asking God to receive this poem, mouth and heart together, as a gift. No one can produce a mouth and heart fully acceptable on their own. One greater servant did, and that is why this prayer can still be prayed by people who are not yet blameless.
Let the light search you today, and ask for the hidden faults. Then pray verse 14 in the name of the one whose words and heart always pleased the Father.
Prayer
Father, your heavens have declared your glory since before we learned to listen, and your law has searched out our hidden places since before we learned to hide. Thank you for a word that revives the soul and makes the simple wise. Keep us back from presumptuous sins, and let the words of our mouths and the meditations of our hearts be acceptable in your sight, through Jesus. Amen.