Behold, he spreadeth his light upon it - That is, upon his tabernacle or dwelling-place - the clouds. The allusion is to lightning, which flashes in a moment over the whole heavens. The image is exceedingly beautiful and graphic. The idea of "spreading out" the light in an instant over the whole of the darkened heavens, is that which Elihu had in his mind, and which impressed him so forcibly. On the difficulty in regard to the translation of the Septuagint here, see Schleusner on the word ἡδὼ hēdō.
And covereth the bottom of the sea - Margin, "roots." The word roots is used to denote the bottom, as being the lowest part of a thing - as the roots of a tree. The meaning is that he covers the lowest part of the sea with floods of waters; and the object of Elihu is to give an exalted conception of the greatness of God, from the fact that his agency is seen in the higlest and the lowest objects. He spreads out the clouds, thunders in his tabernacle, diffuses a brilliant light over the heavens, and at the same time is occupied in covering the bottom of the sea with the floods. He is Lord over all, and his agency is seen every where. The highest and the lowest objects are under his control, and his agency is seen above and below. On the one hand, he covers the thick and dense clouds with light; and on the other, he envelopes the depth of the ocean in impenetrable darkness.

He spreadeth his light upon it - Or, as Mr. Good translates, "He throweth forth from it his flash." These two verses may both have an allusion to the sudden rarefaction of that part of the atmosphere whence the thunder proceeds, by the agency of the electric fluid; the rushing in of the air on each side to restore the equilibrium, which the passage of the fire had before destroyed. The noise produced by this sudden rushing in of the air, as well as that occasioned by the ignition of the hydrogen gas, which is one of the constituents of water, is the thunder of his tabernacle, viz., the atmosphere, where God appears, in such cases, to be manifesting his presence and his power. Elihu says that God spreadeth his light upon it. This is spoken in reference to the flashes and coruscations of lightning in the time of thunder storms, when, even in a dark night, a sudden flash illuminates for a moment the surface of the earth under that place.
And covereth the bottom of the sea - He doth whatsoever it pleaseth him in the heavens above, in the earth beneath, in the sea, and in all deep places. Yea, the depths of the sea are as much under his control and influence as the atmosphere, and its whole collection of vapours, meteors, and galvanic and electric fluids.

Behold, he spreadeth his light upon (u) it, and covereth the (x) bottom of the sea.
(u) Upon the cloud.
(x) That men cannot come to the knowledge of the springs of it.

Behold, he spreadeth his light upon it,.... Upon his tabernacle; that is, upon the clouds, which are his tabernacle; either the light of the sun, whereby the clouds are dispersed and blotted out; an emblem of the blotting out of sin, or the forgiveness of it, Isaiah 44:22, which is like a clear shining after rain, 2-Samuel 23:4, or on a thin cloud, whereby the rainbow is formed, an emblem of peace and reconciliation by Christ; or lightning, which bursting out of the dark cloud is spread over it, when it seems to be all in flames. Cocceius renders it, "he spreads the light about himself"; God spreads it about himself, clothing himself with light as with a garment, and dwelling in light inaccessible to men: or he "spreads it upon him", upon man; causing his sun to shine on the just and unjust; or on it, the earth; so it was spread when first commanded to shine out of darkness, with which the earth in its primeval state was covered; and so it is spread every morning upon the earth; as soon as day breaks, the morning is spread upon the mountains, and in a short time it overspreads the whole hemisphere; an emblem this of the spread of the light of grace over the dark hearts of men, in conversion, which are like the earth in its chaotic state, or as in the night season covered with darkness; out of which they are called and brought by the grace of God, having the true light sprung and placed in their souls; which at first is but glimmering, and at best imperfect in the present state, yet is spreading and increasing, Proverbs 4:18; and of the spread of the great and glorious light of the Gospel in the world, in the times of the apostles, and as it will be in the latter day glory;
and covereth the bottom of the sea, or "the roots of the sea" (n); though one would think they should be rather covered with water and with darkness, as they are; see Job 38:8. This is to be understood either of the light of the sun, and the rays of it, which are so piercing and penetrating as to reach to the bottom of the sea, and cover it and exhale waters out of it; or of lightning, which is equally as piercing and penetrating, or more, and strikes to the very roots of the sea, and covers them, or rather discovers them, so that the channels of waters are seen, and the foundations of the world are discovered, Psalm 18:14; the Targum of this verse is,
"he spreads upon it rain, and covers the rocks or foundations of the sea;''
and the rain is called light according to Ramban, because by the descent of it the day is enlightened, and the darkness of the clouds removed; and by this means the bottom of the sea is covered, so that it passes its bounds and covers the rocks, that is, the borders of it, as others explain it (o).
(n) "radices maris", Pagninus, Montanus, &c. (o) In Bar Tzemach in loc.

light--lightning.
it--His tabernacle (Job 36:29). The light, in an instant spread over the vast mass of dark clouds, forms a striking picture.
spread--is repeated from Job 36:29 to form an antithesis. "He spreads not only clouds, but light."
covereth the bottom--roots.
of the sea--namely, with the light. In the storm the depths of ocean are laid bare; and the light "covers" them, at the same moment that it "spreads" across the dark sky. So in Psalm 18:14-15, the discovering of "the channels of waters" follows the "lightnings." UMBREIT translates: "He spreadeth His light upon Himself, and covereth Himself with the roots of the sea" (Psalm 104:2). God's garment is woven of celestial light and of the watery depths, raised to the sky to form His cloudy canopy. The phrase, "cover Himself with the roots of the sea," is harsh; but the image is grand.

30 Behold, He spreadeth His light over Himself,
And the roots of the sea He covereth.
31 For thereby He judgeth peoples,
He giveth food in abundance.
32 Both hands He covereth over with light,
And directeth it as one who hitteth the mark.
33 His noise announceth Him,
The cattle even that He is approaching.
A few expositors (Hirz., Hahn, Schlottm.) understand the celestial ocean, or the sea of the upper waters, by ים, Job 36:30; but it is more than questionable (vid., on Job 9:8) whether ים is used anywhere in this sense. Others as (Umbr., Ew.) the masses of water drawn up to the sky out of the depths of the sea, on which a Persian passage cited by Stick. (who, however, regards the Waw of ושׁרשׁי as Waw adaequationis) from Schebisteri may be compared: "an exhalation rises up out of the sea, and comes down at God's command upon the deserts." In both cases כּסּה would be equivalent to כסה עליו, obtegit se, which in and of itself is possible. But he who has once witnessed a storm in the neighbourhood of the sea, will decide in favour of one of the three following explanations: (1.) He covereth the uprooted ground of the sea (comp. Psalm 18:15.) with the subsiding waves (Blumenf.); but then Job 36:30 would require to be understood of the light of the brightening sky following the darkness of the storm, which is improbable in respect of Job 36:32. (2.) While the sky is brilliantly lighted up by the lightning, the abysses of the ocean are veiled in a so much deeper darkness; the observation is correct, but not less so another, that the lightning by a thunder-storm, especially when occurring at night, descends into the depths of the sea like snares that are cast down (פּחים, Psalm 11:6), and the water is momentarily changed as it were into a sea of flame; accordingly it may be explained, (3.) Behold, He spreadeth over Himself His light (viz., the light which incessantly illumines the world), and the roots of the sea, i.e., the sea down to its depths, He covers with it, since He makes it light through and through (Stuhlm. Wolfs.). Thus, as it appears, Jerome also interprets: Et (si voluerit) fulgurare lumine suo desuper, cardines quoque maris operiet.
(Note: The Targ. translates אור, Job 36:30, Job 36:32, by מטרא, pluvia, according to the erroneous opinion of R. Jochanan: כל אורה שׁנאמר באליהוא אינו אלא בירידת גשׁמים. Aben-Ezra and Kimchi explain even עלי־אור, Isaiah 18:4, according to this passage. The lxx translates Job 36:30: ἰδοὺ ἐκτενεῖ ἐπ ̓ αὐτὸν ἠδώ (Cod. Alex. επ αυτον το τοξον; Cod. Sinait. επ αυτην ηωδη (with the corrections ηδω and τοξον), probably according to the reading אידו for אורו. But what connection have ἠδώ and rainbow?)
This, that He makes the light of the lightning His manifestation (פּרשׂ עליו), and that He covers the earth down to the roots of the sea beneath with this light, is established in Job 36:31 from the design, partly judicial, partly beneficial, which exists in connection with it. בּם refers as neuter (like בּהם, Job 22:21) to the phenomena of the storm; מכבּיר (with the adverbial ל like לרב, Job 26:3), what makes great = a making great, abundance (only here), is n. hiphil. after the form משׁהית, perdens = perditio. In Job 36:32 God is represented under a military figure as a slinger of lightnings: He covers light over both hands, i.e., arms both completely with light (comp. סכסך and Arab. škk, totum se operire armis), and directs it (עליה referring to אור as fem. like Jeremiah 13:16, and sometimes in the Talmud). But what is the meaning of בּמפגּיע? Hahn takes מפגיע as n. hiphil. like מכביר: an object of attack; but what then becomes of the original Hiphil signification? It ought to be בּמפגּע (Job 7:20), as Olsh. wishes to read it. Ew., Hirz., and others, after the example of Theod. (lxx), Syr., Jeremiah., translate: against the adversary; מפגיע ;yrasre signifies indeed the opposite in Isaiah 49:16 : intercessor (properly, one who assails with prayers); however, it would be possible for this word, just as פגע c. acc. (which signifies usually a hostile meeting, Exodus 5:3 and freq., but sometimes also a friendly, Isaiah 47:3; Isaiah 64:4), to be an ἐναντιόσημον. We prefer to abide by the usage of the language as we have it, according to which הפגיע signifies facere ut quid incurset s. petat, Isaiah 53:6; מפגיע therefore is one who hits, in opposition to one who misses the mark. The Beth is the Beth essentiae (vid., on Job 23:13), used here like Exodus 6:3; Psalm 55:19; Isaiah 40:10. With both hands He seizes the substance of the lightning, fills them with it so that they are completely covered by it, and gives it the command (appoints it its goal), a sure aimer!

Light - The lightning; fitly God's light, because God only can light it. It - Upon the cloud, which is in a manner the candlestick in which God sets up this light. The sea - The lightning spreads far and wide over all the parts of the sea, and pierceth deep, reaching even to the bottom of it.