What danced like a calf?
Rashi: The [Malbim - broken] cedars. Radak (11) - a calf is young, and dances and runs. Hashem will break them and move them from their place; it will seem that they dance due to the noise.
What are "Levanon v'Siryon"?
Rashi: They are names of mountains.
Radak (11) #1: The verse mentions mountains in Eretz Yisrael, for they are close (but the same applies to mountains everywhere).
Radak (11) #2: Nochri kings are called mountains - "he'Harim Yamushu veha'Geva'os Temutenah" (Yeshayah 54:10).
Why does it say "k'Ven Re'emim"?
Radak (11): It is young, quick and dances. So Hashem will move the nations from place to place.
Malbim: The mountains danced like a young Re'em, which is bigger than a calf.
