Sweet Songs Yet to Come
In telling of the great turnaround that will happen, Moshe predicted that the nations of the world will joyfully sing as they watch HaShem bring His people back to Eretz Yisrael.
In the words of Ramban:
“This [prophecy of Moshe] surely refers to the time of Moshiach, because when the Jews returned to Eretz Yisrael and built the Second Beis HaMikdash, the nations were not singing their praises. Just the opposite! They were laughing at them, saying, “What do these Jewish weaklings think they will accomplish?”
Consider this: even the greatest of the Jews were servants to the King of Bavel and they were all under his rule. At that time, HaShem did not bring punishment to the enemies of the Jews…
Clearly this song is a promise of very good things to come in the upcoming redemption [when Moshiach comes]!”