Treading Upon the Asp and the Basilisk: The Serpent's Head and the Power Given
Old Testament: Psalms 90:13
Thou shalt walk upon the asp and the basilisk: and thou shalt trample under foot the lion and the dragon.
Old Testament, also: Genesis 3:15
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.
New Testament: Luke 10:19
Behold, I have given you power to tread upon serpents and scorpions, and upon all the power of the enemy: and nothing shall hurt you.
The connection
The psalm promises the one who dwells in the help of the Most High that he shall walk upon the asp and the basilisk and trample the lion and the dragon (Psalms 90:13). Christ gives the seventy-two exactly that: "power to tread upon serpents and scorpions, and upon all the power of the enemy" (Luke 10:19), in the same breath as "I saw Satan like lightning falling from heaven" (Luke 10:18). Tertullian reads the psalm as Christ's before it is the disciples': "under the figure of scorpions and serpents are portended evil spirits, whose very prince is described by the name of serpent, dragon, and every other most conspicuous beast in the power of the Creator. This power the Creator conferred first of all upon His Christ, even as the ninetieth Psalm says to Him" (Against Marcion IV.24). Irenaeus carries the same line back to Eden: the enmity set between the serpent and the woman lasts "until the seed did come appointed to tread down his head, which was born of Mary, of whom the prophet speaks: 'Thou shalt tread upon the asp and the basilisk; thou shalt trample down the lion and the dragon'" (Against Heresies III.23.7). The heel the serpent lies in wait for in Genesis is the foot that tramples him in the psalm, and the power handed to the disciples is a share in that one victory. Scripture carries the trampling on past the Gospel. Paul promises the Roman church: "the God of peace crush Satan under your feet speedily" (Romans 16:20), the promise of Genesis 3:15 made over to the Church, and the Apocalypse names the enemy for what Eden hid: "that old serpent, who is called the devil and Satan" (Apocalypse 12:9).
Moral sense
The devil knows this psalm. Tempting Christ on the pinnacle of the Temple he quotes the two verses before it, the angels who bear up the foot, and stops one line short. Cassian saw why: "he quoted the one to deceive Him: he held his tongue about the latter to avoid condemning himself. For he knew that he himself was signified by the asp and basilisk, the lion and dragon in the Prophet's words" (On the Incarnation VII.16). Gregory Nazianzen turns on him for it: "O vile sophist! how was it that thou didst suppress the words that follow" (Oration on Holy Baptism). Temptation still works by half a verse, and the defence is the rest of it. Augustine names the two ways the enemy comes: "The lion openly rages, the dragon lies secretly in covert." The martyrs met the lion; the dragon is the quiet deceit. "Thou hast conquered the lion; conquer also the dragon: the lion hath not crushed thee, let not the dragon deceive thee" (Expositions on the Psalms, Psalm 91, 17). Christ adds a warning to the gift: "rejoice not in this, that spirits are subject unto you; but rejoice in this, that your names are written in heaven" (Luke 10:20). The power to tread is given; the joy is kept for being known by God.
Anagogical sense
Irenaeus runs the trampling to the end of history: the lion, "that is, antichrist, rampant against mankind in the latter days, should be trampled down by Him", and He should bind "the dragon the old serpent" (Apocalypse 20:2), until "the last enemy, death, is destroyed". CCC 410 calls Genesis 3:15 the Protoevangelium, "the first announcement of the Messiah and Redeemer, of a battle between the serpent and the Woman, and of the final victory of a descendant of hers". Cyril of Alexandria sees the fall Christ watched already becoming the Church's footing: Satan "fell as lightning, seeing that he is trodden under foot by those who worship Christ" (in the Catena Aurea on Luke 10). The first promise and the last binding are one fight, and the psalm sings its outcome in the future tense: thou shalt trample.
The Fathers
Tertullian, Against Marcion IV.24: "under the figure of scorpions and serpents are portended evil spirits, whose very prince is described by the name of serpent, dragon, and every other most conspicuous beast in the power of the Creator. This power the Creator conferred first of all upon His Christ, even as the ninetieth Psalm says to Him." Irenaeus, Against Heresies III.23.7: "until the seed did come appointed to tread down his head, which was born of Mary, of whom the prophet speaks: 'Thou shalt tread upon the asp and the basilisk; thou shalt trample down the lion and the dragon.'" St John Cassian, On the Incarnation VII.16, on the devil at the temptation: "he quoted the one to deceive Him: he held his tongue about the latter to avoid condemning himself." St Augustine, Expositions on the Psalms, Psalm 91, 17: "The lion openly rages, the dragon lies secretly in covert." St Cyril of Alexandria, in the Catena Aurea on Luke 10:17-20: "he fell as lightning, seeing that he is trodden under foot by those who worship Christ."
Warrant
Luke 10:19 does not quote the psalm, so the badge is patristic, not scriptural. The link is carried in the words as well as the Fathers: in the Latin, Luke's calcandi (to tread) shares its root with the psalm's conculcabis (thou shalt trample) and with calcaneo, the heel of Genesis 3:15, and Luke's inimici (the enemy) with inimicitias (enmities) in Genesis 3:15; the Greek has the same pairs, patein beside katapateseis and echthrou beside echthran. The liturgy keeps the reading: in the traditional Roman Missal the First Sunday of Lent reads the temptation (Matthew 4:1-11) and takes every chant from Psalm 90, its Tract singing verse 13, the line the tempter left out.
Catechism of the Catholic Church, paragraph 410.
