Genesis 3:14

And the Lord God said unto the serpent
And to the devil in it; for what follows may be applied to both; literally to the serpent, and mystically to Satan; both are punished, and that very justly, the serpent in being the instrument Satan made use of, and is cursed for his sake, as the earth for man's; and the punishing the instrument as well as the principal, the more discovers God's detestation of the act for which they are punished, as appears in other instances, ( Exodus 21:28 ) ( Leviticus 20:15 ) . Nor could it have been agreeable to the justice of God, to punish the instrument and let the principal go free; and therefore the following sentence must be considered as respecting them both: and it must be observed, that no pains is taken to convince Satan of his sin, or any time spent in reasoning and debating with him about it, he being an hardened apostate spirit, and doomed to everlasting destruction, and without any hope of mercy and forgiveness; but to show the divine resentment of his crime, the following things are said: because thou hast done this;
beguiled the woman, and drawn her in to eat of the forbidden fruit, [thou art] cursed above all cattle, and above every beast of the
field;
the serpent is the most hateful of all creatures, and especially the most detestable to men, and Satan is accursed of God, banished from the divine presence, is laid up in chains of darkness, and reserved for the judgment of the great day, and consigned to everlasting wrath and ruin, signified by everlasting fire prepared for the devil and his angels; upon thy belly shalt thou go,
or "breast", as Aben Ezra, and others; Jarchi thinks it had feet before, but were cut off on this account, and so became a reptile, as some serpents now have feet like geese, as Pliny ^F24 relates; or it might go in a more erect posture on its hinder feet, as the basilisk, which is one kind of serpent, now does; and if it was a flying one, bright and shining in the air, now it should lose all its glory, and grovel in the dust, and with pain, or at least with difficulty, creep along on its breast and belly; and this, as it respects the punishment of the devil, may signify, that he being cast down from the realms of bliss and glory, shall never be able to rise more, and regain his former place and dignity: And dust shall thou eat all the days of thy life;
meaning not that particular serpent, and as long as that should live, but all of the same kind, as long as there were any in the world, even to the end of it: it is probable, that when the serpent moved in a more erect posture, it lived on herbs and plants as other creatures; but when it was obliged to go upon its belly or breast, it licked up the dust of the earth, and which it could not well avoid in eating whatsoever food it did; and some serpents are said to live upon it. This is applicable to Satan, designs the mean and abject condition in which he is, and the sordid food he lives upon; no more on angels' food and joys of heaven, but on the base, mean, earthly, and impure lusts of men; and this will be his case, condition, and circumstances, for ever.