Albert Barnes Commentary Psalms 19:4

"Their line is gone out through all the earth, And their words to the end of the world. In them hath he set a tabernacle for the sun," — Psalms 19:4 (ASV)

Their line - This refers to the heavens. The word used here—קו qav—properly means a cord or line:

• A measuring line (Ezekiel 47:3; Job 38:5; Isaiah 44:13); and then
• A cord or string, like that of a lyre or other musical instrument, and therefore, a sound.

So it is rendered here by the Septuagint, φθόγγος phthongos; by Symmachus, ἦχος ēchos; and by the Vulgate, sonus. DeWette renders it Klang, sound. Professor Alexander dogmatically says that this is “entirely at variance with the Hebrew usage.” That this sense, however, is demanded in the passage seems clear, not only from the meaning given to it by the ancient versions but also by the parallelism, where the term “words” corresponds to it:

“Their line is gone out through all the earth;
Their words to the end of the world.”

Besides, what could be the meaning of saying that their line, in the sense of a measuring line or cord, had gone through all the earth? The plain meaning is that sounds conveying instruction, and here connected with the idea of sweet or musical sounds, had gone out from the heavens to all parts of the world, conveying the knowledge of God. There is no allusion to the notion of the “music of the spheres,” for this concept was unknown to the Hebrews; rather, the idea is that of sweet or musical sounds, not harsh or grating, which proceed from the movements of the heavens and convey these lessons to humankind.

And their words - The lessons or truths which they convey.

To the end of the world - To the uttermost parts of the earth. This language is derived from the idea that the earth was a plane and had limits. However, even with our correct knowledge of the earth’s shape, we use similar language when we speak of the “uttermost parts of the earth.”

In them - That is, in the heavens (Psalms 19:1). The meaning is that the sun has its abode or dwelling-place, as it were, in the heavens. The sun is particularly mentioned, doubtless, as being the most prominent object among the heavenly bodies, illustrating in an eminent manner the glory of God. The sense of the whole passage is that the heavens in general proclaim the glory of God, and that this is shown in a particular and special way by the light, splendor, and journeyings of the sun.

Hath he set a tabernacle for the sun - A tent; that is, a dwelling-place. He has made a dwelling-place there for the sun. Compare Habakkuk 3:11: “The sun and moon stood still in their habitation.”