Having presented Hashem's victory over Pharaoh and his army (Refer to 15:4:1:1*), what is the Torah discussing now?
Seforno: The Torah is now discussing the destruction of the Egyptians who followed the army as they chased after Yisrael to destroy them. 1
What does the Torah mean by "uv'Ru'ach Apecha"?
Rashbam: It refers to the powerful east wind that caused the water to pile up. 3
Da'as Zekenim: Normally, breath from the mouth is cold, and from the nose is hot. Here was a double miracle - His [hot] breath from the nose froze the water, and His [cold] breath from the mouth melted the frozen water.
Kol Eliyahu: Just like Hashem 'breathed' into Adam, and this gave to him Chachmah, likewise the water received Chachmah 4 , like the Targum says.
What is the meaning of "Ne'ermu Mayim"?
Rashi #2, Seforno, Rashbam and Targum Yonasan: The water piled up into a heap. 3
Kol Eliyahu: It received Chachmah through Hashem's breath, just like Adam did. Refer to 15:8:2:4*.
To pile up, thereby creating a path for Yisrael to pass through and to subsequently drown the Egyptians (See Sifsei Chachamim). Hadar Zekenim - it was able to sing Shirah. See also Peirush Yonasan.
To conform to the next words "Nitz'vu K'mo Neid Nozlim" (Rasi).
What are the connotations of "Kaf'u Tehomos b'Lev Yam"?
Rosh (14:26): Just like a person's heart is a third (below the top of his height), also the heart of the sea. The top third split, and below that congealed. 3 Da'as Zekenim adds, had all the water split down to the Tehom (the sea floor), Bnei Yisrael would not have been able to come up. 4
Rosh: Parshas Tzitzis was written about Yetzi'as Mitzrayim (it is mentioned at the end; also refer to 14:5:154:1,2), therefore Chazal said (Menachos 39a) to make the threads a third windings, and the rest straight.
Because the slope is too steep (PF).