These are wells, or fountains, without water. He shews by these two metaphors, that they had nothing within, though they made a great display. A fountain, by its appearance, draws men to itself, because it promises them water to drink, and for other purposes; as soon as clouds appear, they give hope of immediate rain to irrigate the earth. He then says that they were like fountains, because they excelled in boasting, and displayed some acuteness in their thoughts and elegance in their words; but that yet they were dry and barren within: hence the appearance of a fountain was fallacious. He says that they were clouds carried by the wind, either without rain, or which burst forth into a calamitous storm. He thereby denotes that they brought nothing useful, and that often they were very hurtful. He afterwards denounces on them the dreadful judgment of God, that fear might restrain the faithful. By naming the mist or the blackness of darkness, he alludes to the clouds which obscure the air; as though he had said, that for the momentary darkness which they now spread, there is prepared for them a much thicker darkness which is to continue for ever.

These are wells without water - Jde 1:12-13 employs several other epithets to describe the same class of persons. The language employed both by Peter and Jude is singularly terse, pointed, and emphatic. Nothing to an oriental mind would be more expressive than to say of professed religious teachers, that they were "wells without water." It was always a sad disappointment to a traveler in the hot sands of the desert to come to a well where it was expected that water might be found, and to find it dry. It only aggravated the trials of the thirsty and weary traveler. Such were these religious teachers. In a world, not unaptly compared, in regard to its real comforts, to the wastes and sands of the desert, they would only grievously disappoint the expectations of all those who were seeking for the refreshing influences of the truths of the gospel. There are many such teachers in the world.
Clouds that are carried with a tempest - Clouds that are driven about by the wind, and that send down no rain upon the earth. They promise rain, only to be followed by disappointment. Substantially the same idea is conveyed by this as by the previous phrase. "The Arabs compare persons who put on the appearance of virtue, when yet they are destitute of all goodness, to a light cloud which makes a show of rain, and afterward vanishes" - Benson. The sense is this: The cloud, as it rises, promises rain. The expectation of the farmer is excited that the thirsty earth is to be refreshed with needful showers. Instead of this, however, the wind "gets into" the cloud; it is driven about, and no rain falls, or it ends in a destructive tornado which sweeps everything before it. So of these religious teachers. Instruction in regard to the way of salvation was expected from them; but, instead of that, they disappointed the expectations of those who were desirous of knowing the way of life, and their doctrines only tended to destroy.
To whom the mist of darkness is reserved for ever - The word rendered "mist" here, (ζόφος zophos,) means properly muskiness, thick gloom, darkness, (see 2-Peter 2:4); and the phrase "mist of darkness" is designed to denote "intense" darkness, or the thickest darkness. It refers undoubtedly to the place of future punishment, which is often represented as a place of intense darkness. See the notes at Matthew 8:12. When it is said that this is "reserved" for them, it means that it is prepared for them, or is kept in a state of readiness to receive them. It is like a jail or penitentiary which is built in anticipation that there will be criminals, and with the expectation that there will be a need for it. So God has constructed the great prison-house of the universe, the world where the wicked are to dwell, with the knowledge that there would be occasion for it; and so he keeps it from age to age that it may be ready to receive the wicked when the sentence of condemnation shall be passed upon them. Compare Matthew 25:41. The word "forever" is a word which denotes properly eternity, (εἰς αἰώνα eis aiōna,) and is such a word as could not have been used if it had been meant that they would not suffer forever. Compare the notes at Matthew 25:46.

These are wells without water - Persons who, by their profession, should furnish the water of life to souls athirst for salvation; but they have not this water; they are teachers without ability to instruct; they are sowers, and have no seed in their basket. Nothing is more cheering in the deserts of the east than to meet with a well of water; and nothing more distressing, when parched with thirst, than to meet with a well that contains no water.
Clouds that are carried with a tempest - In a time of great drought, to see clouds beginning to cover the face of the heavens raises the expectation of rain; but to see these carried off by a sudden tempest is a dreary disappointment. These false teachers were equally as unprofitable as the empty well, or the light, dissipated cloud.
To whom the mist of darkness is reserved - That is, an eternal separation from the presence of God, and the glory of his power. They shall be thrust into outer darkness, Matthew 8:12; into the utmost degrees of misery and despair. False and corrupt teachers will be sent into the lowest hell; and be "the most downcast, underfoot vassals of perdition."
It is scarcely necessary to notice a various reading here, which, though very different in sound, is nearly the same in sense. Instead of νεφελαι, clouds, which is the common reading, και ὁμιχλαι, and mists, or perhaps more properly thick darkness, from ὁμου, together, and αχλυς, darkness, is the reading in ABC, sixteen others, Erpen's Arabic, later Syriac, Coptic, Ethiopic, and Vulgate, and several of the fathers. This reading Griesbach has admitted into the text.

(8) These are (o) wells without water, clouds that are carried with a tempest; to whom the mist of (p) darkness is reserved for ever.
(8) Another note by which it may be known what manner of men they are, because they have inwardly nothing but that which is utterly vain or very harmful, although they make a show of some great goodness, yet they shall not escape unpunished for it, because under pretence of false freedom, they draw men into the most miserable slavery of sin.
(o) Who boast of knowledge and have nothing in them.
(p) Most gross darkness.

These are wells without water,.... Which look large and deep, promise much, and have nothing in them; so these men looked like angels of light, transformed themselves as ministers of righteousness, had a form of godliness, and boasted of their great knowledge; promised great advantages to their followers, but were like deceitful brooks, or dry wells, and so disappointed those that came to them, and attended on them; having nothing but the filth and slime of error and iniquity, being destitute both of the grace of God, comparable to water, and of the truth of heavenly doctrine, which is like the rain that fills the wells, pools, and fountains.
Clouds that are carried with a tempest; these false teachers may be compared to clouds for their number, for many antichrists and false prophets soon came into the world; and for their sudden rise in the churches, into which they crept privily and unawares; and because of the general darkness they spread, for when errors and heresies prevail it is a dark and cloudy day with the churches, a day of gloominess and darkness, of thick darkness, a day of trouble, rebuke, and blasphemy; and because of the height of them, especially light clouds, as these are compared to, who are high in their own conceits and imaginations, and think, and give out themselves to be some great persons; and also because of their sudden destruction, which lingers and slumbers not, but comes upon them in a moment, and their glory passes away like the morning cloud: and these may be said to be as clouds "carried with a tempest": of their own lusts and passions, by which they are governed, and are led, and carried away with the force of them, and have no power to resist them, being under the dominion of them, and captives to them; and of Satan's temptations, who works effectually in them, with all power, signs, and lying wonders, and with all deceivableness of unrighteousness, and being taken in his snare, are led captive by him at his will: Jude says, "carried about of winds", Jde 1:12, with every wind of false doctrine, like meteors in the air; are never at a point, always unsteady and unsettled, and ready to embrace every new and upstart notion:
to whom the mist of darkness is reserved for ever; the nature of their punishment is expressed by "darkness", the blackest darkness, the mist of darkness, and which Jude calls blackness of darkness, the same with utter darkness; and which signifies a most forlorn and uncomfortable condition, and is a righteous judgment, and just retaliation upon them who studied to darken counsel by words without knowledge; and the certainty of their punishment is signified by its being "reserved", even as the happiness of the saints, and the safety and sureness of it are represented by an inheritance reserved in heaven: and as God has his treasures, magazines, and stores of grace and mercy, felicity and glory, for his people; so he has his wrath and vengeance reserved, laid up in store with him, and sealed up among his treasures, which he will surely bring forth in his own time: and the duration of this punishment is "for ever"; it is a worm that never dies, a fire that is never quenched, Isaiah 66:24 Mark 9:44; it is everlasting fire and burnings, the smoke of which ascends for ever and ever.

The word of truth is the water of life, which refreshes the souls that receive it; but deceivers spread and promote error, and are set forth as empty, because there is no truth in them. As clouds hinder the light of the sun, so do these darken counsel by words wherein there is no truth. Seeing that these men increase darkness in this world, it is very just that the mist of darkness should be their portion in the next. In the midst of their talk of liberty, these men are the vilest slaves; their own lusts gain a complete victory over them, and they are actually in bondage. When men are entangled, they are easily overcome; therefore Christians should keep close to the word of God, and watch against all who seek to bewilder them. A state of apostacy is worse than a state of ignorance. To bring an evil report upon the good way of God, and a false charge against the way of truth, must expose to the heaviest condemnation. How dreadful is the state here described! Yet though such a case is deplorable, it is not utterly hopeless; the leper may be made clean, and even the dead may be raised. Is thy backsliding a grief to thee? Believe in the Lord Jesus, and thou shalt be saved.

(Jde 1:12-13.)
wells--"clouds" in Jude; both promising (compare 2-Peter 2:19) water, but yielding none; so their "great swelling words" are found on trial to be but "vanity" (2-Peter 2:18).
clouds--The oldest manuscripts and versions read, "mists," dark, and not transparent and bright as "clouds" often are, whence the latter term is applied sometimes to the saints; fit emblem of the children of darkness. "Clouds" is a transcriber's correction from Jde 1:12, where it is appropriate, "clouds . . . without water" (promising what they do not perform); but not here, "mists driven along by a tempest."
mist--blackness; "the chilling horror accompanying darkness" [BENGEL].

These are springs without water. They promise much but disappoint.
Mists driven by a storm. The thought is the same. These mists promise rain, but it fails to descend.
For whom. For these apostates the "blackness of darkness is reserved."
For. This shows how they promise great things and disappoint. They offer great swelling words, and entice those who are about to be delivered from error.
Promising liberty. Liberty from all restraint, complete freedom to serve their own wills, such liberty as those who rail against God's law are wont to offer.
Servants of corruption. Those who offer liberty are themselves slaves, serving their own passions and lusts. He who is swayed by appetite or habit cannot be free.

Fountains and clouds promise water: so do these promise, but do not perform.