For when evil shall be sweet in his mouth, he will hide it under his tongue.

Though he doth sweeten evil in his mouth, Doth hide it under his tongue,

Though evil-doing is sweet in his mouth, and he keeps it secretly under his tongue;

Though wickedness be sweet in his mouth - Though he has pleasure in committing it, as he has in pleasant food. The sense of this and the following verses is, that though a man may have pleasure in indulgence in sin, and may find happiness of a certain kind in it, yet that the consequences will be bitter - as if the food which he ate should become like gall, and he should cast it up with loathing. There are many sins which, from the laws of our nature, are attended with a kind of pleasure. Such, for illustration, are the sins of gluttony and of intemperance in drinking; the sins of ambition and vanity; the sins of amusement and of fashionable life. To such we give the name of "pleasures." We do not speak of them as "happiness." That is a word which would not express their nature. It denotes rather substantial, solid, permanent joy - such joy as the "pleasures of sin for a season" do not furnish. It is this temporary "pleasure" which the lovers of vanity, fashion and dress, seek, and which, it cannot be denied, they often find. As long ago as the time of Zophar, it was admitted that such pleasure might be found in some forms of sinful indulgence and yet even in his time that was seen, which all subsequent observation has proved true, that such indulgence must lead to bitter results.
Though he hide it under his tongue - It is from this passage, probably, that we have derived the phrase, "to roll sin as a sweet morsel under the tongue," which is often quoted as if it were a part of Scripture. The "meaning" here is, that a man would find pleasure in sin, and would seek to prolong it, as one does the pleasure of eating that which is grateful to the palate by holding it long in the mouth, or by placing it under the tongue.

Though wickedness be sweet in his mouth - This seems to refer to the secret sins mentioned above.
Hide it under his tongue - This and the four following verses contain an allegory; and the reference is to a man who, instead of taking wholesome food, takes what is poisonous, and is so delighted with it because it is sweet, that he rolls it under his tongue, and will scarcely let it down into his stomach, he is so delighted with the taste; "he spares it, and forsakes it not, but keeps it still within his mouth," Job 20:13. "But when he swallows it, it is turned to the gall of asps within him," Job 20:14, which shall corrode and torture his bowels.

Though wickedness be (f) sweet in his mouth, [though] he hide it under his tongue;
(f) As poison that is sweet in the mouth brings destruction when it comes into the body: so all vice at the first is pleasant, but God later turns it to destruction.

Though wickedness be sweet in his mouth,.... Which may respect some particular sin, and by the context it seems to be the sin of covetousness, or of getting riches in an unlawful way, which is very sweet and pleasing to wicked men, while they are in such pursuits that succeed; and so Mr. Broughton renders it by "wrong"; though it may be applied to sin in general, which is "wickedness", or an evil (q), being contrary to the pure and holy nature, will, and law of God; and it is evil in its effects on men, it having deprived them of the image and glory of God, and exposed them to his wrath, to the curses of his law, and to eternal deaths. Now this is "sweet" to an unregenerate man, who minds and savours the things of the flesh, whose taste is not changed, but is as it was from his birth, and who calls sweet bitter, and bitter sweet; such a man has the same delight in sin as a man has in his food, drinks up iniquity like water, and commits sin with greediness; for it is natural to him, he is conceived, born, and brought up in it; besides, some sins are what are more particularly called constitution sins, which some are peculiarly addicted to, and in which they take a peculiar delight and pleasure; these are like the right hand or right eye, and they cannot be persuaded, at any rate, to part with them:
though he hide it under his tongue; not for the sake of concealing it, nor by denying, dissembling, or excusing it, but for the sake of enjoying more pleasure in it; as a gluttonous man, when he has got a sweet morsel in his mouth, do not let it go down his throat immediately, but rolls it under his tongue, that he may have all the pleasure of it he can; so a wicked man devises sin in his heart, keeps it on his mind, revolves it in his thoughts, and his meditation on it is sweet; and he is so far from hiding it from others, that he openly declares it, freely tells of it, and takes pleasure in so doing: "fools make a mock at sin"; it is their diversion and recreation.
(q) "malum", Pagninus, Montanus, Junius & Tremellius, Piscator, &c.

be--"taste sweet." Sin's fascination is like poison sweet to the taste, but at last deadly to the vital organs (Proverbs 20:17; Job 9:17-18).
hide . . . tongue--seek to prolong the enjoyment by keeping the sweet morsel long in the mouth (so Job 20:13).

12 If wickedness tasted sweet in his mouth,
He hid it under his tongue;
13 He carefully cherished it and did not let it go,
And retained it in his palate:
14 His bread is now changed in his bowels,
It is the gall of vipers within him.
15 He hath swallowed down riches and now he spitteth them out,
God shall drive them out of his belly.
16 He sucked in the poison of vipers,
The tongue of the adder slayeth him.
The evil-doer is, in Job 20:12, likened to an epicure; he keeps hold of wickedness as long as possible, like a delicate morsel that is retained in the mouth (Renan: comme un bonbon qu'on laisse fondre dans la bouche), and seeks to enjoy it to the very last. המתּיק, to make sweet, has here the intransitive signification dulcescere, Ew. 122, c. הכחיד, to remove from sight, signifies elsewhere to destroy, here to conceal (as the Piel, Job 6:10; Job 15:18). חמל, to spare, is construed with על, which is usual with verbs of covering and protecting. The conclusion of the hypothetical antecedent clauses begins with Job 20:14; the perf. נהפּך (with Kametz by Athnach) describes the suddenness of the change; the מרורת which follows is not equivalent to למרורת (Luther: His food shall be turned to adder's gall in his body), but Job 20:14 expresses the result of the change in a substantival clause. The bitter and poisonous are synonymous in the ancient languages; hence we find the meanings poison and gall (Job 20:25) in מררה, and ראשׁ signifies both a poisonous plant which is known by its bitterness, and the poison of plants like to the poison of serpents (Job 20:16; Deuteronomy 32:33). חיל (Job 20:15) is property, without the accompanying notion of forcible acquisition (Hirz.), which, on the contrary, is indicated by the בּלע. The following fut. consec. is here not aor., but expressive of the inevitable result which the performance of an act assuredly brings: he must vomit back the property which he has swallowed down; God casts it out of his belly, i.e., (which is implied in בּלע, expellere) forcibly, and therefore as by the pains of colic. The lxx, according to whose taste the mention of God here was contrary to decorum, trans. ἐξ οἰκίας (read κοιλίας, according to Cod. Alex.) αὐτοῦ ἐξελκύσει αὐτὸν ἄγγελος (Theod. δυνάστης). The perf., Job 20:15, is in Job 20:16 changed into the imperf. fut. יינק, which more strongly represents the past action as that which has gone before what is now described; and the ασυνδέτως, fut. which follows, describes the consequence which is necessarily and directly involved in it. Psalm 140:4 may be compared with Job 20:16, Proverbs 23:32 with Job 20:16. He who sucked in the poison of low desire with a relish, will meet his punishment in that in which he sinned: he is destroyed by the poisonous deadly bite of the serpent, for the punishment of sin is fundamentally nothing but the nature of sin itself brought fully out.

Mouth - To his taste; though it greatly please him for the present. Hide - As an epicure doth a sweet morsel, which he keeps and rolls about his mouth, that he may longer enjoy the pleasure of it.