How thy garments are warm - What is the reason that the garments which we wear produce warmth? This, it would seem, was one of the philosophical questions which were asked at that time, and which it was difficult to explain. Perhaps it has never occurred to most persons to ask this apparently simple question, and if the inquiry were proposed to them, plain as it seems to be, they would find it as difficult to give an answer as Elihu supposed it would be for Job. Of the fact here referred to that the garments became oppressive when a sultry wind came from the south, there could be no dispute. But what was the precise difficulty in explaining the fact, is not so clear. Some suppose that Elihu asks this question sarcastically, as meaning that Job could not explain the simplest matters and the plainest facts; but there is every reason to think that the question was proposed with entire seriousness, and that it was supposed to involve real difficulty. It seems probable that the difficulty was not so much to explain why the garments should become oppressive in a burning or sultry atmosphere, as to show how the heated air itself was produced It was difficult to explain why cold came out of the north Job 37:9; how the clouds were suspended, and the lightnings caused Job 37:11, Job 37:15-16; and it was not less difficult to show what produced uncomfortable heat when the storms from the north were allayed; when the earth became quiet, and when the breezes blowed from the south. This would be a fair question for investigation, and we may readily suppose that the causes then were not fully known.
When he quieteth the earth - When the piercing blast from the north dies away, and the wind comes round to the south, producing a more gentle, but a sultry air. It was true not only that the whirlwind came from the south Job 37:9, but also that the heated burning air came also from that quarter, Luke 12:55. We know the reason to be that the equatorial regions are warmer than those at the north, and especially that in the regions where Job lived the air becomes heated by passing over extended plains of sand, but there is no reason to suppose that this was fully understood at the time referred to here.

How thy garments are warm - What are warmth and cold? How difficult this question! Is heat incontestably a substance, and is cold none? I am afraid we are in the dark on both these subjects. The existence of caloric, as a substance, is supposed to be demonstrated. Much, satisfactorily, has been said on this subject; but is it yet beyond doubt? I fear not. But supposing this question to be set at rest, is it demonstrated that cold is only a quality, the mere absence of heat? If it be demonstrated that there is such a substance as caloric, is it equally certain that there is no such substance as frigoric? But how do our garments keep us warm? By preventing the too great dissipation of the natural heat. And why is it that certain substances, worked into clothing, keep us warmer than others? Because they are bad conductors of caloric. Some substances conduct off the caloric or natural heat from the body; others do not conduct it at all, or imperfectly; hence those keep us warmest which, being bad conductors of caloric, do not permit the natural heat to be thrown off. In these things we know but little, after endless cares, anxieties, and experiments!
But is the question yet satisfactorily answered, why the north wind brings cold, and the south wind heat? If it be so to my readers, it is not so to me; yet I know the reasons which are alleged.

How thy garments [are] (n) warm, when he quieteth the earth by the south [wind]?
(n) Why your clothes should keep you warm when the south wind blows rather than when any other wind blows?

How thy garments are warm, when he quieteth the earth by the south wind? One should think there is no great difficulty in accounting for this, that a man's clothes should be warm, and he so hot as not to be able to bear them, but obliged to put them off in the summer season, when only the south wind blows, which brings heat, a serene sky, and fine weather, Luke 12:55; and yet there is something in the concourse of divine Providence attending these natural causes, and his blessing with them, without which the garment of a man will not be warm, or at least not warming to him, Haggai 1:6; or
"how thy garments are warm when the land is still from the south,''
as Mr. Broughton renders the words; that is, how it is when the earth is still from the whirlwinds of the south; or when that wind does not blow which brings heat, but northerly winds in the winter time; that then a man's garments should be warm, and keep him warm.

thy garments, &c.--that is, dost thou know how thy body grows warm, so as to affect thy garments with heat?
south wind--literally, "region of the south." "When He maketh still (and sultry) the earth (that is, the atmosphere) by (during) the south wind" (Song 4:16).

17 Thou whose garments became hot,
When the land is sultry from the south:
18 Dost thou with Him spread out the sky,
The strong, as it were molten, mirror?
19 Let us know what we shall say to Him! -
We can arrange nothing by reason of darkness.
20 Shall it be told Him that I speak,
Or shall one wish to be destroyed?
Most expositors connect Job 37:17 with Job 37:16 : (Dost thou know) how it comes to pass that ; but אשׁר after ידע signifies quod, Exodus 11:7, not quomodo, as it sometimes occurs in a comparing antecedent clause, instead of כאשׁר, Exodus 14:13; Jeremiah 33:22. We therefore translate: thou whose , - connecting this, however, not with Job 37:16 (vid., e.g., Carey), but as Bolduc. and Ew., with Job 37:18 (where ה before תרקיע is then the less missed): thou who, when the land (the part of the earth where thou art) keeps rest, i.e., in sultriness, when oppressive heat comes (on this Hiph. vid., Ges. 53, 2) from the south (i.e., by means of the currents of air which come thence, without דּרום signifying directly the south wind), - thou who, when this happens, canst endure so little, that on the contrary the heat from without becomes perceptible to thee through thy clothes: dost thou now and then with Him keep the sky spread out, which for firmness is like a molten mirror? Elsewhere the hemispheric firmament, which spans the earth with its sub-celestial waters, is likened to a clear sapphire Exodus 24:10, a covering Psalm 104:2, a gauze Isaiah 40:22; the comparison with a metallic mirror (מוּצק here not from צוּק, Job 37:10; Job 36:16, but from יצק) is therefore to be understood according to Petavius: Coelum areum στερέωμα dicitur non a naturae propria conditione, sed ab effectu, quod perinde aquas separet, ac si murus esset solidissimus. Also in תרקיע lies the notion both of firmness and thinness; the primary notion (root רק) is to beat, make thick, stipare (Arab. rq‛, to stop up in the sense of resarcire, e.g., to mend stockings), to make thick by pressure. The ל joined with תרקיע is nota acc.; we must not comp. Job 8:8; Job 21:22, as well as Job 5:2; Job 19:3.
Therefore: As God is the only Creator (Job 9:8), so He is the all-provident Preserver of the world - make us know (הודיענוּ, according to the text of the Babylonians, Keri of הודיעני) what we shall say to Him, viz., in order to show that we can cope with Him! We cannot arrange, viz., anything whatever (to be explained according to ערך מלּין, Job 32:14, comp. "to place," Job 36:19), by reason of darkness, viz., the darkness of our understanding, σκότος τῆς διανοίας; מפּני is much the same as Job 23:17, but different from Job 17:12, and חשׁך different from both passages, viz., as it is often used in the New Testament, of intellectual darkness (comp. Ecclesiastes 2:14; Isaiah 60:2). The meaning of Job 37:20 cannot now be mistaken, if, with Hirz., Hahn, and Schlottm., we call to mind Job 36:10 in connection with אמר כּי: can I, a short-sighted man, enshrouded in darkness, wish that what I have arrogantly said concerning and against Him may be told to God, or should one earnestly desire (אמר, a modal perf., as Job 35:15) that (an jusserit s. dixerit quis ut) he may be swallowed up, i.e., destroyed (comp. לבלעו, Job 2:3)? He would, by challenging a recognition of his unbecoming arguing about God, desire a tribunal that would be destructive to himself.

Quieteth - The air about the earth. From the south - By the sun's coming into the southern parts, which makes the air quiet and warm.