That was definitely a tough verse. Here is Matthew Henry. Kudos to those who are deep into its meanings. Talk about chewing on spiritual meat instead of milk!
The prisoners being found guilty by their own confession, besides the personal and infallible knowledge of the Judge, and nothing material being offered in arrest of judgment, God immediately proceeds to pass sentence; and, in these verses, he begins (where the sin began) with the serpent. God did not examine the serpent, nor ask him what he had done nor why he did it; but immediately sentenced him, 1. Because he was already convicted of rebellion against God, and his malice and wickedness were notorious, not found by secret search, but openly avowed and declared as Sodoms. 2. Because he was to be for ever excluded from all hope of pardon; and why should any thing be said to convince and humble him who was to find no place for repentance? His wound was not searched, because it was not to be cured. Some think the condition of the fallen angels was not declared desperate and helpless, until now that they had seduced man into the rebellion.
I. The sentence passed upon the tempter may be considered as lighting upon the serpent, the brute-creature which Satan made use of which was, as the rest, made for the service of man, but was now abused to his hurt. Therefore, to testify a displeasure against sin, and a jealousy for the injured honour of Adam and Eve, God fastens a curse and reproach upon the serpent, and makes it to groan, being burdened. See Rom. 8:20. The devils instruments must share in the devils punishments. Thus the bodies of the wicked, though only instruments of unrighteousness, shall partake of everlasting torments with the soul, the principal agent. Even the ox that killed a man must be stoned, Ex. 21:28, 29. See here how God hates sin, and especially how much displeased he is with those who entice others into sin. It is a perpetual brand upon Jeroboams name that he made Israel to sin. Now, 1. The serpent is here laid under the curse of God: Thou art cursed above all cattle. Even the creeping things, when God made them, were blessed of him (ch. 1:22), but sin turned the blessing into a curse. The serpent was more subtle than any beast of the field (v. 1), and here, cursed above every beast of the field. Unsanctified subtlety often proves a great curse to a man; and the more crafty men are to do evil the more mischief they do, and, consequently, they shall receive the greater damnation. Subtle tempters are the most accursed creatures under the sun. 2. He is here laid under mans reproach and enmity. (1.) He is to be for ever looked upon as a vile and despicable creature, and a proper object of scorn and contempt: "Upon thy belly thou shalt go, no longer upon feet, or half erect, but thou shalt crawl along, thy belly cleaving to the earth, an expression of a very abject miserable condition, Ps. 44:25; "and thou shalt not avoid eating dust with thy meat. His crime was that he tempted Eve to eat that which she should not; his punishment was that he was necessitated to eat that which he would not: Dust thou shalt eat. This denotes not only a base and despicable condition, but a mean and pitiful spirit; it is said of those whose courage has departed from them that they lick the dust like a serpent, Mic. 7:17. How sad it is that the serpents curse should be the covetous worldlings choice, whose character it is that he pants after the dust of the earth! Amos 2:7. These choose their own delusions, and so shall their doom be. (2.) He is to be for ever looked upon as a venomous noxious creature, and a proper object of hatred and detestation: I will put enmity between thee and the woman. The inferior creatures being made for man, it was a curse upon any of them to be turned against man and man against them; and this is part of the serpents curse. The serpent is hurtful to man, and often bruises his heel, because it can reach no higher; nay, notice is taken of his biting the horses heels, ch. 49:17. But man is victorious over the serpent, and bruises his head, that is, gives him a mortal wound, aiming to destroy the whole generation of vipers. It is the effect of this curse upon the serpent that, though that creature is subtle and very dangerous, yet it prevails not (as it would if God gave it commission) to the destruction of mankind. This sentence pronounced upon the serpent is much fortified by that promise of God to his people, Thou shalt tread upon the lion and the adder (Ps. 91:13), and that of Christ to his disciples, They shall take up serpents (Mk. 16:18), witness Paul, who was unhurt by the viper that fastened upon his hand. Observe here, The serpent and the woman had just now been very familiar and friendly in discourse about the forbidden fruit, and a wonderful agreement there was between them; but here they are irreconcilably set at variance. Note, Sinful friendships justly end in mortal feuds: those that unite in wickedness will not unite long.
II. This sentence may be considered as levelled at the devil, who only made use of the serpent as his vehicle in this appearance, but was himself the principal agent. He that spoke through the serpents mouth is here struck at through the serpents side, and is principally intended in the sentence, which, like the pillar of cloud and fire, has a dark side towards the devil and a bright side towards our first parents and their seed. Great things are contained in these words.
1. A perpetual reproach is here fastened upon that great enemy both to God and man. Under the cover of the serpent, he is here sentenced to be, (1.) Degraded and accursed of God. It is supposed that the sin which turned angels into devils was pride, which is here justly punished by a great variety of mortifications couched under the mean circumstances of a serpent crawling on his belly and licking the dust. How art thou fallen, O Lucifer! He that would be above God, and would head a rebellion against him, is justly exposed here to contempt and lies to be trodden on; a mans pride will bring him low, and God will humble those that will not humble themselves. (2.) Detested and abhorred of all mankind. Even those that are really seduced into his interest yet profess a hatred and abhorrence of him; and all that are born of God make it their constant care to keep themselves, that this wicked one touch them not, 1 Jn. 5:18. He is here condemned to a state of war and irreconcilable enmity. (3.) Destroyed and ruined at last by the great Redeemer, signified by the breaking of his head. His subtle politics shall all be baffled, his usurped power shall be entirely crushed, and he shall be for ever a captive to the injured honour of divine sovereignty. By being told of this now he was tormented before the time.
2. A perpetual quarrel is here commenced between the kingdom of God and the kingdom of the devil among men; war is proclaimed between the seed of the woman and the seed of the serpent. That war in heaven between Michael and the dragon began now, Rev. 12:7. It is the fruit of this enmity, (1.) That there is a continual conflict between grace and corruption in the hearts of Gods people. Satan, by their corruptions, assaults them, buffets them, sifts them, and seeks to devour them; they, by the exercise of their graces, resist him, wrestle with him, quench his fiery darts, force him to flee from them. Heaven and hell can never be reconciled, nor light and darkness; no more can Satan and a sanctified soul, for these are contrary the one to the other. (2.) That there is likewise a continual struggle between the wicked and the godly in this world. Those that love God account those their enemies that hate him, Ps. 139:21, 22. And all the rage and malice of persecutors against the people of God are the fruit of this enmity, which will continue while there is a godly man on this side heaven, and a wicked man on this side hell. Marvel not therefore if the world hate you, 1 Jn. 3:13.