Rabbi Meir takes the tradition further than either Rabbi Yossi or Rebbi. Even fetuses in their mothers' wombs, he declares, opened their mouths and chanted song before God at the Red Sea. The miracle of the Song was not limited to those who had been born, or to those who could speak, or even to those who had taken their first breath. Unborn children, still enclosed in the womb, participated in the praise.
His proof text comes from Psalms: "In assemblies bless God — the Lord, from the source of Israel" (Psalms 68:27). Rabbi Meir reads "from the source of Israel" as a reference to the womb — the literal source from which every Israelite emerges. Even from that source, from inside the womb, blessing went forth to God. The assemblies that blessed God at the sea included members who had not yet been born into the world.
But Rabbi Meir does not stop with human beings. He adds that Israel was not alone in singing — the ministering angels also chanted song before God. His proof: "How mighty is Your name in all the earth — You who have spread Your splendor on the heavens!" (Psalms 8:2). The splendor spread upon the heavens represents the angelic praise that accompanied the earthly song. At the Red Sea, the Mekhilta envisions a cosmic chorus — fetuses in the womb, infants at the breast, children, adults, and the hosts of heaven, all singing together in a single moment of universal recognition that God had acted.