Their line - That is, of the heavens. The word used here - קו qav - means properly a cord, or line:
(a) a measuring line, Ezekiel 47:3; Job 38:5; Isaiah 44:13; and then
(b) a cord or string as of a lyre or other instrument of music; and hence, a sound.
So it is rendered here by the Septuagint, φθόγγος phthongos. By Symmachus, ἦχος ēchos. By the Vulgate, sonus. DeWette renders it Klang, sound. Prof. Alexander dogmatically says that this is “entirely at variance with the Hebrew usage.” That this sense, however, is demanded in the passage seems to be plain, not only from the sense given to it by the ancient versions, but 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 sense 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 conception was not known to the Hebrews; but the idea is that of sweet or musical sounds, not harsh or grating, as proceeding from the movements of the heavens, and conveying these lessons to man.
And their words - The lessons or truths which they convey.
To the end of the world - To the uttermost parts of the earth. The language here is derived from the idea that the earth was a plane, and had limits. But even with our correct knowledge of the figure of the earth, 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 his 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, as 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 manner by the light, the splendor, and the 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.”