Upon the wicked he shall rain snares, fire and brimstone, and an horrible tempest: this shall be the portion of their cup. Upon the wicked he shall rain - This is a manifest allusion to the destruction of Sodom and Gomorrah.
Snares - Judgments shall fall upon them suddenly and unawares.
Fire - Such as shall come immediately from God, and be inextinguishable.
Brimstone - Melted by the fire, for their drink! This shall be the portion of their cup.
A horrible tempest - רוח זלעפות roach zilaphoth, "the spirit of terrors." Suffering much, and being threatened with more, they shall be filled with confusion and dismay. My old MS. has "gost of stormis." See at the end, Psalms 11:7 (note). Or, the blast of destructions. This may refer to the horribly suffocating Arabian wind, called Smum.
Mohammed, in describing his hell, says, "The wicked shall drink nothing there but hot stinking water; breathe nothing but burning winds; and eat nothing but the fruit of the tree zakon, which shall be in their bellies like burning pitch." Hell enough!
The portion of their cup - Cup is sometimes put for plenty, for abundance; but here it seems to be used to express the quantum of sorrow and misery which the wicked shall have on the earth. See Psalms 75:8; Isaiah 51:17, Isaiah 51:21-23; Jeremiah 25:15; Jeremiah 49:12; Lamentations 4:21, Lamentations 4:22. It is also used in reference to the afflictions of the righteous, Matthew 20:22; Matthew 26:39, Matthew 26:42; John 18:11.
We find a similar metaphor among the heathens. The following, from Homer, Il. xxiv., ver. 525, is in point: -
Ὡς γαρ επεκλωσαντο θεοι δειλοισι βροτοισι,
Ζωειν αχνυμενους· αυτοι δε τ' ακηδεες εισι,
Δοιοι γαρ τε πιθοι κατακειαται εν Διος ουδει
Δωρων, οια διδωσι, κακων· ἑτερος δε εαων·
Ὡ μεν καμμιξας δῳη Ζευς τερπικεραυνος,
αλλοτε μεν τε κακῳ ὁγε κυρεται, Αλλοτε δ' εσθλῳ.
Such is, alas! the god's severe decree,
They, only they are bless'd, and only free.
Two urns by Jove's high throne have ever stood,
The source of evil one, and one of good.
From thence the Cup of mortal man he fills:
Blessings to these; to those distributes ills.
To most he mingles both: the wretch decreed
To taste the bad unmixed, is curs'd indeed.
- Pope.