The passuk states “ויאמר מצרים אנוסה מפני ישראל כי ה’ נלחם להם במצרים.” Rashi explains: We shall flee from before Yisrael because Hashem is fighting against the Egyptians for them, and we better leave or we will be terminated. Rashi brings another explanation that מצרים is literal, the place of Egypt. The Egyptians said “Just as these are being struck by the Yam so to those who remained in Egypt are getting the same punishment.”
Onkelos translates the words כי ה’ נלחם להם במצרים as, “this is the might of Hashem that battled for them in Egypt.” Avi Mori shlita explained that this is like the first opinion in the Mechilta: the Egyptians recognized by the Yam Suf that Hashem who is striking them here is the same Hashem who fought against them on behalf of Yisrael the entire time. He is the one who sent all the makos and performed all the miracles in Egypt.
There is a pressing question on both Onkelos’ and Rashi’s 2nd explanation. The Egyptians said that Hashem is smiting the place of Egypt and the Egyptians in Egypt while they were situated at the Yam. How could the Egyptians by the Yam Suf have possibly known what was happening to those in Egypt?
The Mechilta brings that Rebi Yosi said: Hashem performed a miracle and they were able to see the Egyptians in Mitzrayim getting smitten!
The passuk states “ומצרים נסים לקראתו.” Rashi explains that the Egyptians were in turmoil and they ran towards the water. Onkelos explains as the Mechilta: wherever the Egyptians fled the water flowed opposite them to block them from escaping!
The Ramban says that Hashem caused the eastern wind to blow and look as though the wind split the sea and therefore the Egyptians would continue to chase them. Although winds don’t split seas, they did not pay attention to this and they entered into the sea because of their great desire to do bad. They did not remember that Hashem fought for them in Mitzrayim, despite saying this themselves a moment before.
The Egyptians saw that the Yam was split before Bnei Yisrael and they were walking inside the sea on dry land. How could the Egyptians have the audacity to do bad? This is indeed absurd! The Ramban says that there is no greater wonder than this from all of Hashem’s wonders! Hashem strengthened their hearts to make them do something foolish in order to punish them for their wickedness.
May we learn from these amazing miracles by the Yam Suf to recognize Hashem and accept Him as King!