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Exploring "Yishretsu" in Genesis 1:20 A Dive into Movement, Swarming, and More

Genesis 1:20 declares, "And God said, ‘Let the waters yishretsu with swarms of living creatures, and let birds fly above the earth across the expanse of the heavens.’" The Hebrew verb yishretsu (from the root sharatz) is a fascinating term that has sparked varied interpretations about what God commanded the waters to do on the fifth day of creation. Did it mean "to move," "to swarm," or perhaps both? Scholars like Nachmanides, Radak, and ancient translations like the Septuagint and Vulgate offer different angles. By examining these views, challenging some, and connecting yishretsu to a later verse with Noah, we’ll see why "swarm" might be the best fit—capturing both motion and abundance—and wrap up with my take on it.

Nachmanides: "To Move" – A Limited View?

Nachmanides (Ramban) interpreted yishretsu as "to move," focusing on the idea of living creatures stirring or darting through the water. He saw it as God animating the waters with motion, fitting his broader view of creation as a dynamic process from nothing. While movement is part of the picture—fish and sea life certainly don’t sit still—this take feels narrow. The root sharatz appears elsewhere, like in Exodus 8:3 (Hebrew 7:28), where frogs "swarm" over Egypt, suggesting not just motion but teeming abundance. If yishretsu only meant "to move," it might miss this sense of prolific life filling the waters, which Genesis 1’s context—creation bursting forth—seems to emphasize. Nachmanides’ focus on motion alone doesn’t fully grab the verb’s richness.

In Genesis 9:7, God tells Noah and his sons, "Be fruitful and multiply (p’ru urvu); shirtzu on the earth and multiply in it," where shirtzu (from sharatz) suggests abundant reproduction or swarming. This challenges Nachmanides’ view of yishretsu as simply "to move," since shirtzu follows p’ru urvu (a clear command to reproduce) and seems tied to bringing forth life, not just motion, aligning more with the idea of teeming or producing abundantly.

Septuagint and Vulgate: "Move" Persists

The Septuagint (LXX) translates yishretsu as exagageto (ἐξαγαγέτω), meaning "let it bring forth" or "produce," but in some contexts, it implies movement out or along, aligning with "to move." The Vulgate uses producant (from producere), "to produce" or "bring forth," which can also hint at creatures moving into existence or activity. Both translations lean toward motion or emergence, supporting Nachmanides’ idea to some extent. But this choice softens the Hebrew’s vividness. Sharatz isn’t just about producing or moving—it’s about swarming multitudes, like insects or fish teeming in droves. The Greek and Latin shift the focus slightly, losing some of the "swarm" intensity for a broader "move forth" sense.

Radak: Both "Move" and "Swarm"

Radak (David Kimchi), a medieval commentator, offers a balanced view: yishretsu means both "to move" and "to swarm." He saw the root sharatz as capturing creatures that scurry about (movement) while multiplying in great numbers (swarming). This dual sense fits the word’s use—like in Leviticus 11:29-30, where "swarming things" (sheretz) are small, active critters. Radak’s take bridges Nachmanides’ motion with the teeming life implied elsewhere, suggesting the waters buzzed with both activity and abundance. It’s a compelling middle ground, recognizing that fish and sea creatures don’t just move—they swarm in schools or clusters, filling the seas.

"Shirtzu" to Noah: Swarming or Reproducing?

Later, in Genesis 9:7, God tells Noah and his sons, "And you, be fruitful and multiply; shirtzu on the earth and multiply in it." This verb, also from sharatz, is often translated "abound" or "multiply abundantly," tying it to reproduction. But it could echo "swarm" too—humanity spreading out like a teeming mass across the land. The context leans toward prolific growth post-flood, yet the swarming nuance lingers: not just more people, but a bustling, active presence. This parallel strengthens the case that yishretsu in Genesis 1:20 carries both abundance and motion, much like Radak suggests, rather than just "move" as Nachmanides argued.

Here’s some additional information on how Ibn Ezra viewed yishretsu in Genesis 1:20 as a transitive verb, how this aligns with the transitive verbs in the Septuagint and Vulgate, and a simple explanation of what a transitive verb is, all woven into a concise section.

Ibn Ezra’s Transitive Take, Plus Greek and Latin

Abraham Ibn Ezra, a 12th-century Jewish scholar, saw yishretsu in Genesis 1:20 as a transitive verb, meaning it acts directly on an object. A transitive verb is a word that needs an object to complete its meaning—like "kick" in "She kicked the ball." The action ("kicked") goes directly to something ("the ball"). Without an object, it feels incomplete. In contrast, an intransitive verb, like "run" in "He runs," stands alone without needing an object. For yishretsu, if it’s transitive (per Ibn Ezra), the waters "swarm forth creatures"; if intransitive, they just "swarm" by themselves.

According Ibn Ezra, the waters don’t just "swarm" on their own; they "swarm forth" or "produce" the living creatures as the object of God’s command. This shifts the focus: the waters actively bring forth swarms, not just teem internally. The Septuagint supports this with exagageto (ἐξαγαγέτω), a transitive verb meaning "let it bring forth" or "produce," where the waters are causing the creatures to emerge. The Vulgate follows suit with producant (from producere, like our word produce), another transitive verb meaning "to bring forth" or "to produce," again with the waters acting on the "living creatures" as the object. Both Greek and Latin translations align with Ibn Ezra’s view by using transitive verbs, emphasizing the waters’ role in actively generating life, not just being a passive backdrop for swarming.

Tying It Together

Ibn Ezra’s transitive reading of yishretsu—the waters producing swarms—matches the Septuagint’s exagageto and Vulgate’s producant, both transitive verbs that make the waters the doer acting on the creatures. This contrasts with a simpler "swarm" (intransitive), where the waters might just teem internally. It’s a subtle but cool twist: the waters aren’t just alive—they’re birthing life, reinforcing the creation’s active burst. "Swarm" as a translation can still work if we see it as shorthand for "swarm forth," keeping that transitive vibe Ibn Ezra, the Greek, and the Latin highlight.

Why "Swarm forth" Wins

"Swarm" might be the best translation for yishretsu because it grabs both ideas—movement and multiplication—in one vivid word. Picture fish darting in schools or insects buzzing in clouds: "swarm" captures the lively motion Nachmanides saw and the teeming numbers Radak and the Hebrew root imply. The Septuagint and Vulgate’s "move forth" or "produce" lose some of that swarm-like energy, while "move" alone misses the quantity. Modern translations like the NASB ("teem") and NIV ("teem with swarms") lean this way, reflecting sharatz’s full flavor over a flat "move," but “teem” is an intransitive verb. That is why “swarm forth” seems to be the most accurate translation in English. In Genesis 9:7, “abound” or “multiply abundantly” could perhaps work, but "swarm" really captures the idea of humanity multiplying and spreading like a living wave, but it perhaps sound a bit awkward as a command in English, whereas in Hebrew, it sounds poetic.