That Old Serpent: The Serpent of Eden and the Great Red Dragon
Old Testament: Genesis 3:1, 15
Now the serpent was more subtle than any of the beasts of the earth which the Lord God had made. And he said to the woman: Why hath God commanded you, that you should not eat of every tree of paradise? ... I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel.
Old Testament, also: Psalms 73:13-14
Thou by thy strength didst make the sea firm: thou didst crush the heads of the dragons in the waters. Thou hast broken the heads of the dragon: thou hast given him to be meat for the people of the Ethiopians.
New Testament: Apocalypse 12:3-4, 9-10, 17
And there was seen another sign in heaven: and behold a great red dragon, having seven heads, and ten horns: and on his heads seven diadems: And his tail drew the third part of the stars of heaven, and cast them to the earth: and the dragon stood before the woman who was ready to be delivered; that, when she should be delivered, he might devour her son. ... And that great dragon was cast out, that old serpent, who is called the devil and Satan, who seduceth the whole world; and he was cast unto the earth, and his angels were thrown down with him. And I heard a loud voice in heaven, saying: Now is come salvation, and strength, and the kingdom of our God, and the power of his Christ: because the accuser of our brethren is cast forth, who accused them before our God day and night. ... And the dragon was angry against the woman: and went to make war with the rest of her seed, who keep the commandments of God, and have the testimony of Jesus Christ.
The connection
The first enemy in Scripture is a serpent in a garden, more subtle than any beast, who speaks to the woman and brings death into the world. God curses it and makes a promise in the same breath: "I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel" (Genesis 3:15). The last book of Scripture shows the same enemy grown to its full size. "A great red dragon, having seven heads, and ten horns" stands before a woman in labour, waiting to devour her child; the child is caught up to God, war breaks out in heaven, and the dragon is thrown down. Then St John names him, so that no one can miss it: "that great dragon was cast out, that old serpent, who is called the devil and Satan, who seduceth the whole world" (Apocalypse 12:9). The serpent's first recorded words were a question about what God had said; his last are drowned out, as "a loud voice in heaven" cries that "the accuser of our brethren is cast forth" (Apocalypse 12:10). The serpent of Eden and the dragon of the Apocalypse are one creature. Even the words of the first promise return. The woman, the serpent and her seed stand together again, and the dragon goes "to make war with the rest of her seed" (Apocalypse 12:17). St Irenaeus reads the whole arc as one story. God "put enmity between the serpent and the woman and her seed", "until the seed did come appointed to tread down his head, which was born of Mary", and so that He "should bind the dragon, that old serpent and subject him to the power of man, who had been conquered." The Catechism calls Genesis 3:15 "the first announcement of the Messiah and Redeemer, of a battle between the serpent and the Woman" (CCC 410), and reads the twelfth chapter of the Apocalypse of both Mary and the Church: "Then the dragon was angry with the woman, and went off to make war on the rest of her offspring" (CCC 2853).
Moral sense
The serpent did not begin with a roar; it began with a question, "Why hath God commanded you?", asked politely, of someone who had no reason yet to be afraid. By the end of Scripture he has seven heads, but that is what he became by being listened to. Every sin starts in the garden voice, subtle and reasonable, casting doubt on whether God really meant what He said, and grows by being fed. That is why the fight is lost or won early, at the question and not the dragon. St Paul feared this: "lest, as the serpent seduced Eve by his subtilty, so your minds should be corrupted, and fall from the simplicity that is in Christ" (2 Corinthians 11:3). The enemy is crushed not by the one who argues best with him but by the woman's seed, by staying close to Christ and to His Mother.
Anagogical sense
The serpent was cursed to eat the earth all the days of his life, and the Apocalypse shows where the days end: the dragon is bound, and at the last cast into the lake of fire, and there is no more sea for him to rise from. The war begun at the tree of paradise ends at the tree of life, open again to the children of the woman. What was promised in the garden, a head crushed and a heel bitten, is seen fulfilled in heaven: the heel was bitten and the head crushed at Calvary, the empty tomb showed it, and the woman whom the dragon pursued is crowned with twelve stars.
The Fathers
St Irenaeus, Against Heresies III.23: "For this end did He put enmity between the serpent and the woman and her seed", "until the seed did come appointed to tread down his head, which was born of Mary", and that He should bind "the dragon, that old serpent" and subject him to the power of man, who had been conquered. Theonas of Alexandria: "bruise the head of that ancient serpent, who is ever on the watch with all subtlety to undo your good works and your prosperous attainments."
Warrant
Scriptural because Apocalypse 12:9 and 20:2 name the dragon "that old serpent" and "the old serpent", ho ophis ho archaios, the same word ophis the Septuagint uses for the serpent of Genesis 3. The vocabulary of the first promise returns in the Greek: Genesis 3:15 sets enmity between the serpent, the woman (gynaikos) and her seed (spermatos autes), and Apocalypse 12:17 has the dragon make war on "the rest of her seed", ton loipon tou spermatos autes. The texts differ on who crushes the head: the Douay follows the Vulgate's ipsa, she, the Septuagint has autos, he, and the Hebrew hu, he or it, meaning her seed; the Church reads the victory as Christ's, won with and through His Mother, and the entry keeps both. The Psalm is not quoted in the Apocalypse. Its Latin, which the Douay follows, has heads of the dragons in verse 13 and of the dragon in verse 14; the site's Septuagint (Swete) keeps only the plural in verse 13, and the Hebrew there names the one beast Leviathan.
Catechism of the Catholic Church, paragraph 410.
The verses
Genesis 3:1 · Genesis 3:15 · Psalms 73:13 · Psalms 73:14 · Apocalypse 12:3 · Apocalypse 12:4 · Apocalypse 12:9 · Apocalypse 12:10 · Apocalypse 12:17