Genesis 1:20–23

Verse 20: "God said, 'Let the waters abound with living creatures, and let birds fly above the earth in the open expanse of the sky.'"

The Fifth Day marks a momentous threshold in the creation narrative: for the first time, God calls forth nephesh chayyah — "living souls" or "living creatures" — beings possessing the vital breath of animated life. The Hebrew verb yishretzu ("let them swarm" or "teem") conveys an image of exuberant, almost overwhelming abundance. This is no sparse or tentative emergence; it is a torrential outpouring of life. St. Basil the Great, in his Hexaemeron (Homily VII), marvels at the sheer prodigality implied here: "Let the waters bring forth" is a command that unleashes not a trickle of life but a cascade — from the invisible organisms of the tidal pools to the great creatures of the deep.

Structurally, this verse parallels the Second Day (vv. 6–8), where God separated the waters below from the expanse (raqia') above. What was then an empty architectural space is now filled with inhabitants. The pattern of the creation week thus reveals itself as one of forming followed by filling: Days 1–3 establish the domains; Days 4–6 populate them. The waters and the sky, fashioned on Day Two, now receive their proper denizens on Day Five. This literary architecture, widely recognized by scholars such as Henri Blocher and noted in Catholic commentary by Cardinal Ratzinger (In the Beginning), underscores that creation is not arbitrary but proceeds according to a divine wisdom — a logos — that orders all things purposefully.

Note that God addresses the waters with an imperative: "Let the waters abound." The waters are, in a sense, instrumental — called to cooperate in bringing forth life under divine command. St. Thomas Aquinas (Summa Theologiae I, q. 72) observes that this does not imply the waters possess creative power of their own, but rather that God employs secondary causes, dignifying the created order by making it a participant in His creative work. This principle — that God acts through creation, not merely upon it — is foundational for Catholic theology of nature and grace alike.

Verse 21: "God created the large sea creatures and every living creature that moves, with which the waters swarmed, after their kind, and every winged bird after its kind. God saw that it was good."

Here the narrator shifts from divine command (v. 20) to divine execution, and notably reintroduces the verb bara' — "created" — which has appeared only once before, in the absolute beginning of Genesis 1:1. Its reappearance here is theologically significant. The Priestly author reserves bara' for acts that represent genuinely new orders of being: the original creation of heaven and earth, and now the emergence of animate life (nephesh chayyah). Something ontologically new has entered the world — not merely a rearrangement of existing matter, but a new mode of existence: sentient, moving, living being. St. Augustine (De Genesi ad Litteram III.11) sees this as confirmation that life is not a mere epiphenomenon of matter but a fresh expression of divine creative power.

The tanninim gedolim — "great sea creatures" — deserve special attention. In the broader ancient Near Eastern context, these creatures evoke primordial chaos monsters: Tiamat of Babylonian myth, Lotan/Leviathan of Canaanite lore. Yet Genesis deliberately demythologizes them. They are not rival deities or remnants of a cosmic battle; they are creatures, called into being by God's sovereign word and subject to His ordering will. As the Catechism teaches (CCC 285), Scripture here "corrects" pagan cosmogonies, affirming that nothing in creation stands outside God's dominion. The great sea creatures are not adversaries but testimonies to divine power and artistry.

The phrase "after their kind" (l'minehu), repeated for both sea creatures and birds, establishes what the Fathers called the rationes seminales — the principle that life possesses inherent order and distinction. Each species reflects a particular divine idea. St. Basil exhorts his hearers: "Let the earth bring forth — and immediately each kind appeared, bearing the seal of the Creator's intention." This is not a scientific taxonomy but a theological affirmation: the diversity of life is neither accidental nor chaotic, but is the expression of God's inexhaustible creative wisdom.

The refrain "God saw that it was good" (ki tov) now takes on added resonance. It is one thing for inert elements — light, seas, vegetation — to be declared good. It is another for living beings, with their capacity for movement, sensation, and interaction, to receive this divine approbation. Goodness here encompasses vitality itself.

Verse 22: "God blessed them, saying, 'Be fruitful, and multiply, and fill the waters in the seas, and let birds multiply on the earth.'"

This is the first blessing (vaybárekh) in all of Scripture — a detail of enormous theological weight. God has spoken commands of separation and formation; He has declared things good. But now, for the first time, He blesses. The Hebrew barakh implies the conferral of power, potency, and divine favor. It is not merely an observation or wish but an efficacious act: God endows these creatures with the capacity and mandate for fecundity. Life is not simply permitted to continue; it is empowered and commissioned to proliferate.

St. John Chrysostom (Homilies on Genesis VII.5) draws out the implication: the blessing reveals that fertility and multiplication are not autonomous biological processes but divine gifts, sustained by God's ongoing will. The command "Be fruitful and multiply" (peru u'revu) — which will be repeated to humanity in Genesis 1:28 — first belongs to the animal kingdom, establishing a continuity between all living beings as recipients of God's generative blessing. Yet the repetition to Adam and Eve will carry additional weight, as we shall see.

The triple command — be fruitful, multiply, fill — conveys an overflowing plenitude. God does not create sparingly. The seas are to teem; the skies are to be filled. Pope Francis, in Laudato Si' (§69), reflects on precisely this passage: "Each creature possesses its own particular goodness and perfection... Each of the various creatures, willed in its own being, reflects in its own way a ray of God's infinite wisdom and goodness." The Fifth Day's blessing grounds the Catholic conviction that biodiversity is not merely an ecological value but a theological one — each species, blessed into being, reflects something of God that no other creature can.

Verse 23: "There was evening and there was morning, a fifth day."

The formulaic closure of the day anchors this explosion of life within the measured cadence of the creation week. Evening precedes morning — a pattern reflecting the ancient Israelite reckoning of days from sunset to sunset, preserved in Catholic liturgical practice to this day (the vigil Mass, Vespers as the beginning of the liturgical day). But there is also a spiritual rhythm here: darkness yields to light, formlessness yields to fullness. Each day moves from potential to actualization, from evening's hiddeness to morning's revelation. The Fifth Day closes with the world immeasurably richer than it was — no longer silent and still, but alive with the movement and song of creatures who bear, in their very being, the blessing of their Maker.

The Fifth Day occupies a pivotal position in the theology of creation, and Catholic tradition has drawn from it several interconnected teachings of enduring importance.

Creation as Gift and the Ontology of Life. The reappearance of bara' in verse 21 signals that animate life constitutes a genuinely new order of being — not merely a rearrangement of existing matter. The Catechism of the Catholic Church (CCC 308) affirms that God is "the first cause who operates in and through secondary causes," and the Fifth Day illustrates this: the waters are commanded to bring forth, yet it is God who truly creates. This interplay of divine sovereignty and creaturely participation anticipates the entire Catholic theology of grace and nature — God works through His creation without being diminished or displaced by it.

The First Blessing and the Sacramentality of Life. That the first divine blessing in Scripture is bestowed upon fish and birds — not upon humanity — carries a profound implication: blessing, fecundity, and the goodness of embodied life are woven into the fabric of creation prior to and independent of human agency. The Fourth Lateran Council (1215) affirmed that God created all things good "from nothing" — spiritual and corporeal alike. The blessing of verse 22 grounds the Catholic sacramental imagination: material creation is not inert or profane but is charged with divine favor and purpose. As Gerard Manley Hopkins wrote, echoing this tradition, "The world is charged with the grandeur of God."

Typological and Spiritual Senses. The Church Fathers consistently read the waters of creation typologically as prefiguring the waters of Baptism — the waters that first teemed with life now become, in the New Covenant, the womb of spiritual rebirth (cf. CCC 1218). St. Ambrose (De Sacramentis I.15) writes: "You have seen water; but not all water heals — only water that has the grace of Christ... the water is not operative without the Spirit." The creatures emerging from the deep are thus read as figures of the faithful emerging from the baptismal font into new life. Similarly, the birds soaring above the earth are taken by Origen and others as symbols of the soul ascending toward contemplation of God — creatures of the lower realm reaching upward toward the raqia', the firmament of heaven.

Ecological Theology. Pope Francis's Laudato Si' (§33, §69) draws directly on this passage to articulate the Church's teaching that creation's goodness and diversity are not merely resources for human use but intrinsic reflections of divine wisdom. The loss of any species, Francis warns, is the loss of a unique word that God has spoken. The Fifth Day's lavish, blessed abundance thus stands as a permanent call to stewardship, wonder, and reverence before the living world that God Himself declared good and blessed into perpetual fruitfulness.

In an age of ecological crisis and accelerating species extinction, Genesis 1:20–23 speaks with urgent relevance to Catholic readers. The Church's tradition, richly developed in Pope Francis's encyclical Laudato Si', reminds us that every creature — from the smallest fish to the soaring eagle — exists because God willed it into being, blessed it, and called it good. This passage invites Catholics to see care for the natural world not as a political issue but as a deeply spiritual one: to harm creation is to dishonor the Creator's gift. The divine blessing pronounced over the creatures of sea and sky also calls us to a posture of wonder and gratitude in our daily lives, recognizing that the biodiversity surrounding us is a living testimony to God's generosity and love. Stewardship of creation is thus an act of worship.