The Mekhilta takes the worldwide rejection of idolatry at the Red Sea and projects it forward into the future. What happened momentarily at the sea — when all nations opened their mouths and declared "Who is like You among the mighty" — will happen permanently at the end of days.
The proof comes from the prophets. (Jeremiah 16:19) envisions the nations approaching God and confessing: "The Lord is my strength and my stronghold and my refuge on the day of affliction." Then comes the devastating question in verse 20: "Can a man make gods for himself?" The answer, obviously, is no — and the nations will finally admit it.
(Isaiah 2:20) paints an even more vivid picture of that day: "A man will throw away his false gods" — physically casting them aside, discarding them like refuse. Verse 21 explains why: they will flee "to enter the clefts of rocks" in terror, hiding from the overwhelming reality of God's presence. And (Isaiah 2:18) delivers the final verdict: "The false gods will perish completely."
This teaching from the Mekhilta DeRabbi Yishmael (Tractate Shirah 8:3) draws a direct line from the Red Sea to the messianic future. The lot of idolatry — its inevitable fate — was revealed at the sea and will be fulfilled at the end. Every false god will be thrown away. Every idol will perish. The song that the nations began at the Red Sea will one day become their permanent anthem.