Hast thou entered into the springs of the sea? - The word here rendered "springs" (נבך nêbek), occurs nowhere else in the Scriptures. It is rendered by the Vulgate "profunda," the deep parts; and by the Septuagint πηγὴν pēgēn - "fountains." The reference seems to be to the deep fountains at the bottom of the sea, which were supposed to supply it with water. A large portion of the water of the ocean is indeed conveyed to it by rivers and streams that run on the surface of the earth. But it is known, also, that there are fountains at the bottom of the ocean, and in some places the amount of water that flows from them is so great, that its action is perceptible at the surface. One such fountain exists in the Atlantic ocean near the coast of Florida.
Or hast thou walked in the search of the depth? - Or, rather, in the deep places or caverns of the ocean. The word rendered "search" here (חקר chêqer), means "searching," investigation, and then an object that is to be searched out, and hence, that which is obscure, remote, hidden. Then it may be applied to the deep caverns of the ocean, or the bottom of the sea. This is to man unsearchable. No line has been found long enough to fathom the ocean, and of course what is there is unknown. It is adduced, therefore, with great propriety as a proof of the wisdom of God, that he could look on the deep caverns of the ocean, and was able to search out all that was there. A sentiment similar to this occurs in Homer, when speaking of Atlas:
Ὅατε θαλάσσης;
Πάσης βένθεα οἷδεν.
Hoate thalassēs;
Pasēs benthea oiden.
Odyssey Job 1:5.
"Who knows the depths of every sea."

Hast thou entered into the springs of the sea? - Of these springs, inlets, or outlets of the sea, we know just as much as Job. There was prevalent among philosophers an opinion, that through a porous bottom fresh matter was constantly oozing by which the sea was supplied with new materials. But through such pores these materials might as well ooze out as ooze in.
Walked in the search of the depth? - Hast thou walked from the shallow beach through the great ocean's bed, till thou hast arrived at its profoundest depths? In other words, Dost thou know the depths of the sea? Job, we may presume, did not. No man since him has found them out. In multitudes of places they are unfathomed by any means hitherto used by man.

Hast thou entered into the springs of the sea? or hast thou walked in the search of the (m) depth?
(m) If you are not able to seek out the depth of the sea, how much less are you able to comprehend the counsel of God?

Hast thou entered into the springs of the sea?.... The subterraneous passages through which the waters flow into the sea and supply it; or the springs and fountains that rise up at the bottom of it (i); and some tell us of springs of sweet water that rise there, even though the water at the bottom of the sea is saltier than on the surface (k): some render it "the drops of the sea" (l); hast thou considered them and counted them? art thou able to do it? no: others the "perplexities" of it (m), so the Targum, the word being used in this sense, Exodus 14:3; the thickets of it; some speak of woods and forests in it; see Gill on Exodus 10:19; others "rocks" and shelves (n), and others the "borders" of it (o); and the sense then is, hast thou entered into and travelled through the main ocean, observed the forests in it, the shelving rocks and sandy mountains in it, and gone to the utmost borders of it?
or hast thou walked in the search of the depth? to find out the deepest place of it, where no sounding line can reach (p); or walked in quest of the curiosities of it, animals, plants and minerals, unknown to men; or of the riches that lie at the bottom of it, for which now the diving bell is used, but not invented and known in the times of Job; and if Job had not done and could not do all this, how should he be able to enter into the secret springs of Providence, or trace the ways of God, whose way is in the sea, and whose paths are in the great waters, and his footsteps not known? Psalm 77:19.
(i) According to Dr. Plot, the principal fountains have their origin, and are supplied with water through subterraneous passages from the sea. De Origine Fontium, &c. apud Acts. Erudit. Lips. A. M. 1685. p. 538. See Genesis vii. 11. (k) Vid. Scheucbzer. Physic. Sacr. vol. 4. p. 803. (l) "guttas maris", Tigurine version, Grotius. (m) "Perplexitates maris", Munster. (n) "Scopulos maris", Michaelis; "salebrosa maris", Schultens. (o) So Jarchi. (p) For though the greatest depth of the sea is said by Fabianus (apud Plin. Nat. Hist. l. 2, c. 102.) to be fifteen furlongs, or near two miles, this must be understood of that part of it which is fathomable and nearer land. But such as those, called Bathea Ponti, the depths of the Pontus, and are almost three hundred furlongs from the continent, they are said (Plin. ib.) to be of an immense depth, and the bottom not to be found. And if the Sardinian sea, the deepest in the Mediterranean (Aristot. Meteorolog. l. 2, c. 1.) is a thousand orgies or fathoms deep, (Posidonius apud Strabo. Geograph. l. 1, p. 37.) that is, one mile and a fifth, what must the depth of the vast ocean be?

springs--fountains beneath the sea (Psalm 95:4-5).
search--Rather, "the inmost recesses"; literally, "that which is only found by searching," the deep caverns of ocean.

16 Hast thou reached the fountains of the sea,
And hast thou gone into the foundation of the deep?
17 Were the gates of death unveiled to thee,
And didst thou see the gates of the realm of shades?
18 Hast thou comprehended the breadth of the earth?
Speak, in so far as thou knowest all this!
19 Which is the way to where the light dwelleth,
And darkness, where is its place,
20 That thou mightest bring it to its bound,
And that thou mightest know the paths of its house?
21 Thou knowest it, for then wast thou born,
And the number of thy days is great! -
The root נב has the primary notion of obtruding itself upon the senses (vid., Genesis, S. 635), whence נבך in Arabic of a rising country that pleases the eye (nabaka, a hill, a hillside), and here (cognate in root and meaning נבע, Syr. Talmud. נבג, Arab. nbg, nbṭ, scatuirire) of gushing and bubbling water. Hitzig's conjecture, approved by Olsh., נבלי, sets aside a word that is perfectly clear so far as the language is concerned. On חקר vid., on Job 11:7. The question put to Job in Job 38:17, he must, according to his own confession, Job 26:6, answer in the negative. In order to avoid the collision of two aspirates, the interrogative ה is wanting before התבּננתּ, Ew. 324, b; התבנן עד signifies, according to Job 32:12, to observe anything carefully; the meaning of the question therefore is, whether Job has given special attention to the breadth of the earth, and whether he consequently has a comprehensive and thorough knowledge of it. כּלּהּ refers not to the earth (Hahn, Olsh., and others), but, as neuter, to the preceding points of interrogation. The questions, Job 38:19, refer to the principles of light and darkness, i.e., their final causes, whence they come forth as cosmical phenomena. ישׁכּן־אור is a relative clause, Ges. 123, 3, c; the noun that governs (the Regens) this virtual genitive, which ought in Arabic to be without the art. as being determined by the regens, is, according to the Hebrew syntax, which is freer in this respect, הדּרך (comp. Ges. 110, 2). That which is said of the bound of darkness, i.e., the furthest point at which darkness passes away, and the paths to its house, applies also to the light, which the poet perhaps has even prominently (comp. Job 24:13) before his mind: light and darkness have a first cause which is inaccessible to man, and beyond his power of searching out. The admission in Job 38:21 is ironical: Verily! thou art as old as the beginning of creation, when light and darkness, as powers of nature which are distinguished and bounded the one by the other (vid., Job 26:10), were introduced into the rising world; thou art as old as the world, so that thou hast an exact knowledge of its and thine own contemporaneous origin (vid., Job 15:7). On the fut. joined with אז htiw denioj . regularly in the signification of the aorist, vid., Ew. 134, b. The attraction in connection with מספּר is like Job 15:20; Job 21:21.

Springs - Hebrews. the tears; the several springs out of which the waters of the sea flow as tears do from the eyes. Walked - Hast thou found out the utmost depth of the sea, which in divers places could never be reached by the wisest mariner? And how then canst thou fathom the depths of my counsels?