The theme in this chapter is the glory of God, praise, grace, and prayer.
Matthew Henry said this of Psalm 19,
“There are two excellent books which the great God has published for the instruction and edification of the children of men; this psalm treats of them both, and recommends them both to our diligent study. I. The book of the creatures, in which we may easily read the power and godhead of the Creator (v. 1–6). II. The book of the scriptures, which makes known to us the will of God concerning our duty. He shows the excellency and usefulness of that book (v. 7–11), and then teaches us how to improve it (v. 12–14).”