What do we learn from "v'Avar ba'Yam Tzarah"?
Sanhedrin 103b: Michah took an idol through the Yam Suf 1 . (Alternatively, he took a plate with Hashem's name, which Moshe had used to raise Yosef's coffin from the bottom of the Nile. Later he used it to make the Egel.)
Rashi: An affliction will pass over Tzor, which sits in the sea, and it is the head of Tzor's kingdom.
Radak: The nations, which are numerous like the sea, an affliction will pass over them. Avar is masculine; it refers to Devar Tzarah (a matter of affliction).
Malbim: The verse depicts the affliction as a turbulent sea. Even though there will be many afflictions and the birth-pangs of Mashi'ach, they will pass the sea b'Shalom.
Vilna Gaon: He did not take an idol. Rather, he had a spiritual defect that would later cause him to make one.
What do we learn from "v'Hikah va'Yam Galim"?
Rashi: Hashem struck waves in the sea, in order to sink Tzor.
Radak: Hashem struck the sea (Yam Suf) and its waves and dried them, i.e. multitudes of nations - "v'Hovishu Kol Metzulos Ye'or", like it explains "v'Hurad Ge'on Ashur..."
Malbim: Hashem will dry the sea to enable Yisrael to return from Galus - "v'Hecherim Hashem Es Leshon Yam Egypt v'Henif Yado Al ha'Nahar" (Yeshayah 11:15).
What are "Kol Metzulos Ye'or"?
Rashi: It is [Malbim - the river of] Egypt.
Refer to 10:11:2:2.
Why does it specify Egypt and Ashur?
Radak: They harmed Yisrael more than other nations.
Malbim: Before, they ruled over Yisrael, and they will fall with the nations that will gather for the war of Gog and Magog, like I explained in Yechezkel, Perakim 32, 38].