Catholic Commentary
Clean and Unclean Birds and Winged Creatures (Part 2)
19All winged creeping things are unclean to you. They shall not be eaten.20Of all clean birds you may eat.
Deuteronomy 14:19–20 classifies all winged insects as ritually unclean and forbidden for consumption, while permitting the eating of clean birds. This dietary distinction reflects the Torah's broader purity system, where creatures that blur categorical boundaries—such as insects that crawl yet fly—are deemed incompatible with ritual holiness.
Winged insects that cling to the earth teach us to notice what appears elevated but remains rooted in corruption—the spiritual danger is not the obvious vice, but the counterfeit.
Catholic tradition, drawing on the fourfold sense of Scripture articulated by John Cassian and codified in the Catechism of the Catholic Church (§115–119), illuminates these two spare verses at multiple levels simultaneously.
At the literal level, the Church recognizes that these laws served genuine purposes in Israel's life: hygienic (swarming insects were vectors of disease in the ancient Near East), social (Israel's table fellowship marked its separation from Canaanite practice), and pedagogical. The Catechism, following St. Thomas Aquinas (Summa Theologiae I-II, q. 102, a. 6), teaches that the ceremonial precepts of the Old Law had reasons both figurative and literal. Aquinas specifically notes that unclean animals represented vices to be avoided — the winged creeping thing, moving between the earth and the air without fully belonging to either, typifies the double-minded person of James 1:8, unstable in all his ways.
At the allegorical level, the distinction between the clinging insect and the soaring clean bird anticipates the New Covenant's call to transformation. St. Peter's vision in Acts 10 — where God declares all foods clean — is not a contradiction of Deuteronomy but its fulfillment: what the dietary laws encoded typologically (holiness through discernment and separation) is now achieved ontologically through Baptism and the indwelling Spirit. The Christian is made clean from within (cf. Mark 7:19; CCC §582).
At the moral level, the passage remains permanently instructive. The Church Fathers consistently read the binary of clean/unclean as an exhortation to the discernment of spirits (diakrisis), a virtue central to Catholic spiritual theology from Origen through Ignatius of Loyola's Spiritual Exercises. The "winged creeping things" become a lasting image of spiritual counterfeits: things that appear elevated but are rooted in corruption.
For contemporary Catholics, these two verses offer a surprisingly practical lens for what might be called the discipline of spiritual ingestion — what we allow to enter us through our eyes, ears, and minds, not only through our mouths. The Catechism's teaching on social communication (§2496) and the consistent papal tradition from Inter Mirifica through Laudate Deum warn against the consumption of media, entertainment, and ideology that is spiritually "swarming" — superficially elevated (it flies!) but rooted in materialism, cynicism, or moral confusion.
The clean/unclean binary is not a call to scrupulosity or a suspicious withdrawal from the world. Notice the generosity of verse 20: all clean birds may be eaten — the permission is broad. The Church does not call Catholics to anxious avoidance of everything in culture, but to cultivated discernment. St. John Paul II's theology of the body, Ignatius's rules for discernment of spirits, and even the simple Lenten disciplines of fasting and abstinence all train this faculty.
Ask concretely: What do I regularly "consume" — in entertainment, conversation, online content — that swarms between the earthly and the elevated without truly ascending? And conversely, am I freely enjoying the clean gifts God has permitted?
Commentary
Verse 19: "All winged creeping things are unclean to you. They shall not be eaten."
The Hebrew phrase underlying "winged creeping things" (sherets ha-of) refers to swarming, winged insects — the same category prohibited in Leviticus 11:20–23, where the law is given in fuller detail. The root sharats carries the sense of teeming, crawling abundance — creatures that swarm the ground even as they can fly, belonging neither cleanly to the air nor to the earth. Their ambiguous, hybrid character — between sky and soil — appears to be at the heart of their ritual impurity. The purity laws of Deuteronomy and Leviticus consistently associate uncleanness with creatures that blur categorical boundaries (fish without fins or scales; animals that chew the cud but do not have split hooves; insects that crawl yet fly). The prohibition is categorical: all (kol) such creatures are unclean. There is no individual discernment required — the rule is comprehensive. Yet Leviticus 11:21–22 carves out a notable exception for certain locusts, crickets, and grasshoppers that have jointed legs for leaping — a detail Deuteronomy does not repeat here, suggesting Moses is drawing attention to the general principle rather than the exceptions. The word "unclean" (tamé) is a cultic and moral category: contact with the unclean disrupts one's relationship with the holy community gathered before God. Ingesting the unclean is more intimate still — it is a disorder introduced into the body of the covenant person.
Verse 20: "Of all clean birds you may eat."
The positive permission stands in deliberate contrast. The word tahor (clean) is the same root used throughout the Torah for ritual purity and for the vessels and offerings of the sanctuary. The brevity of verse 20 is theologically intentional: permission is given freely and broadly. The clean is not catalogued with the same exhaustive suspicion as the unclean. This mirrors a broader principle in Torah: life and blessing are expansive, while the restrictions, though real, are bounded. Clean birds — those listed earlier in verses 11–18 by exclusion (all that are not the birds of prey, carrion-eaters, and night-hunters listed) — represent the wholesome, the ordered, the creatures whose lives do not depend on death and corruption.
Typological and Spiritual Senses
The Church Fathers, following Origen and Barnabas, read the dietary laws as types of moral discernment. Winged creeping things — creatures that appear to soar but remain bound to the crawling earth — become images of those whose apparent spiritual elevation masks an inner attachment to base, earthly things. They fly, but they swarm. They rise, but they return to corruption. In contrast, the clean bird becomes a figure of the soul raised by grace toward God: genuinely airborne, nourished by what is pure, moving freely in the upper registers of the spiritual life. The Epistle of Barnabas (c. 9–10) reads the clean/unclean distinction as an exhortation to "cleave to those who fear God" and avoid the company of those who are spiritually corrupt — the dietary law becomes a law of association and formation. Jerome similarly insists that the body is formed by what it eats, and the soul by what it dwells on.