Heavier than the sand of the sea - That is, they would be found to be insupportable. Who could bear up the sands of the sea? So Job says of his sorrows. A comparison somewhat similar is found in Proverbs 27:3.
Heavy is a stone, and weighty the sand of the Sea,
But a fool's wrath is heavier than them both.
My words are swallowed up - Margin, "I want words to express my grief." This expresses the true sense - but not with the same poetic beauty. We express the same idea when we say that we are choked with grief; we are so overwhelmed with sorrow that we cannot speak. Any very deep emotion prevents the power of utterance. So in Psalm 77:4 :
Thou holdest mine eyes waking:
I am so troubled that I cannot speak.
So the well-known expressions in Virgil,
Obstupui, steteruntque comae, et vox faucibus haesit.
There has been, however, considerable variety in the interpretation of the word here rendered swallowed up - לוּע lûa‛. Gesenius supposes that it means to speak rashly, to talk at random, and that the idea is, that Job now admits that his remarks had been unguarded - "therefore were my words rash." The same sense Castell gives to the Arabic word. Schultens renders it, "therefore are my words tempestuous or fretful." Rosenmuller, "my words exceed due moderation." Castellio, "my words fail." Luther, "therefore it is vain that I speak." The Septuagint, "but my words seem to be evil." Jerome, "my words are full of grief." In this variety it is difficult to determine the meaning; but probably the old interpretation is to be retained, by which the word is derived from לוּע lûa‛, to absorb, to swallow up; compare Proverbs 20:25; Obadiah 1:16; Job 39:30; Proverbs 23:2. The word does not elsewhere occur.

Heavier than the sand of the sea - This includes two ideas: their number was too great to be counted; their weight was too great to be estimated.

For now it would be heavier than the sand of the sea: therefore my words are (b) swallowed up.
(b) My grief is so great that I lack words to express it.

For now it would be heavier than the sand of the sea,.... Or "seas" (z); all sand is heavy in its own nature, Proverbs 27:3; especially the sand of the sea, that which is immediately taken out of it; for that on the shore is lighter, being dried by the winds and heat of the sun, but the other is heavier, through the additional weight of water; and much more especially how heavy must all the sand of the sea be, and of all the seas that are in the world: yet Job suggests by this hyperbolical expression, exaggerating his case, that his affliction was heavier than it all, a most intolerable and insupportable burden; the afflictions of God's people are but light when compared with what their sins deserve, with the torments of the damned in hell, with the sufferings of Christ in their room and stead, and with everlasting, happiness, the eternal weight of glory, 2-Corinthians 4:17; but in themselves they are heavy, and press hard; they are so to flesh and blood, and especially unless everlasting arms are put under men, and they are supported and upheld with the right hand of God's righteousness; they are heavy when attended with the hidings of God's face, and a sense of his wrath and displeasure, which was Job's case, see Job 13:24; some render "it more copious", or "numerous" (a), and indeed the word has this signification, as in Numbers 20:20; and the metaphor is more frequently used to express a multitude, even what is innumerable, Hosea 1:10; yet the notion of heaviness best agrees with the preceding figure of weighing in balances, and therefore at least is not to be excluded some learned men take in both, as the sense of the word, the number of afflictions, and the bulk and weight of them:
therefore my words are swallowed up; either by his friends, as Kimchi, who heard them, and put a wrong construction on them, without thoroughly examining the true sense of them; as men that swallow down their food greedily, do not chew it, nor take the true taste of it, and so are no judges whether it is good or bad; but this sense seems to have no connection with what goes before; rather they were swallowed up by himself, and the meaning either is, that such was the weight and pressure of his afflictions, that he wanted words to express it; his words "failed" him, as the Targum: or they "come short", as Mr. Broughton renders it; they were not sufficient to set forth and declare the greatness of his troubles; or he faltered in his speech, he could not speak out plainly and distinctly, because of his grief and sorrow, see Psalm 77:4; what he had said was delivered amidst sighs and sobs, through the heaviness of the calamity on him; they were but half words, attended with groanings that could not be uttered; by which he would signify, that though his friends had charged him with speaking too much and too freely, he had not spoken enough, nor could he, by reason of the greatness of his affliction; and also to excuse his present answer, if it was not delivered with that politeness and fulness of expression, with that eloquence and strength of reasoning and discoursing he at other times was capable of: or rather the words may be rendered, "therefore my words break out with heat" (b); in a vehement manner, in a hot and passionate way I am blamed for; but this is to be imputed to the burden of affliction and sorrow upon me, which, if considered, some allowances would be made, and the charge be alleviated.
(z) "marium", Pagninus, Montanus, Mercerus, Piscator, Michaelis, Schultens. (a) "copiosior et gravior est", Michaelis; so Schultens. (b) "propterea verba mea aestuantia sunt", Schultens.

the sand-- (Proverbs 27:3).
are swallowed up--See Margin [that is, "I want words to express my grief"]. But Job plainly is apologizing, not for not having had words enough, but for having spoken too much and too boldly; and the Hebrew is, "to speak rashly" [UMBREIT, GESENIUS, ROSENMULLER]. "Therefore were my words so rash."

Sea - Which is heavier than dry sand. Swallowed - My voice and spirit fail me. I cannot find, or utter words sufficient to express my sorrow or misery.