Adam Clarke Bible Commentary
I will not conceal his parts - This is most certainly no just translation of the original. The Vulgate is to this effect: I will not spare him: nor yield to his powerful words, framed for the purpose of entreaty.
Mr. Good applies it to leviathan: -
"I cannot be confounded at his limbs and violence;
The strength and structure of his frame."
The Creator cannot be intimidated at the most formidable of his own works: man may and should tremble; God cannot.
Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary
12 I will not keep silence about his members,
The proportion of his power and the comeliness of his structure.
13 Who could raise the front of his coat of mail?
Into his double teeth-who cometh therein?
14 The doors of his face-who openeth them?
Round about his teeth is terror.
The Ker לו authorized by the Masora assumes an interrogative rendering: as to it, should I be silent about its members (לו at the head of the clause, as Lev 7:7-9; Isa 9:2), - what perhaps might appear more poetic to many. החרישׁ (once, Job 11:3, to cause to keep silence) here, as usually: to be silent. בּדּיו, as Job 18:13. דּבר signifies the relation of the matter, a matter of fact, as דּברי, facts, Psa 65:4; Psa 105:27; Psa 145:5. חין (compared by Ew. with הין, a measure) signifies grace, χάρις (as synon. חסד), here delicate regularity, and is made easy of pronunciation from חנן, just as the more usual חן; the language has avoided the form חנן, as observed above. לבוּשׁ . clothing, we have translated "coat of mail," which the Arab. libâs usually signifies; פּני לבוּשׁו is not its face's covering (Schlottm.), which ought to be לבוּשׁ פּניו; but פּני is the upper or front side turned to the observer (comp. Isa 25:7), as Arab. wjh, (wag'h), si rem desuper spectes, summa ejus pars, si ex adverso, prima (Fleischer, Glossae, i. 57). That which is the "doubled of its mouth" (רסן, prop. a bit in the mouth, then the mouth itself) is its upper and lower jaws armed with powerful teeth. The "doors of the face" are the jaws; the jaws are divided back to the ears, the teeth are not covered by lips; the impression of the teeth is therefore the more terrible, which the substantival clause, Job 41:14 (comp. Job 39:20), affirms. שׁנּיו gen. subjecti: the circle, ἓρκος, which is formed by its teeth (Hahn).
Jamieson-Fausset-Brown Bible Commentary
I will not conceal--a resumption of the description broken off by the digression, which formed an agreeable change.
his power--literally, "the way," that is, true proportion or expression of his strength (so Hebrew, Deu 19:4).
comely proportion--literally, "the comeliness of his structure" (his apparatus: so "suit of apparel" Jdg 17:10) [MAURER]. UMBREIT translates, "his armor." But that follows after.
John Gill Bible Commentary
I will not conceal his parts,.... The parts of the leviathan; or "his bars", the members of his body, which are like bars of iron:
nor his power; which is very great, whether of the crocodile or the whale:
nor his comely proportion; the symmetry of his body, and the members of it; which, though large, every part is in just proportion to each other.