What is so important about the splitting of the sea? The Haggadah implies it is five times greater than anything that happened in Egypt. Why? We can see in the text that Israel is not supposed to simply pray and wait in faith, like they did in Egypt. Rather, they are told to travel.
This is a metaphor for taking the right actions and taking initiative. The Haggadah is noting that the salvation that occures through our actions is five times as great as that which comes through heaven alone. This explains the Gemara in Ketubot.
רַבִּי יוֹסֵי הַגְּלִילִי אוֹמֵר: מִנַּיִן אַתָּה אוֹמֵר שֶׁלָּקוּ הַמִּצְרִים בְּמִצְרַיִם עֶשֶׂר מַכּוֹת וְעַל הַיָּם לָקוּ חֲמִשִּׁים מַכּוֹת? בְּמִצְרַיִם מַה הוּא אוֹמֵר? וַיֹּאמְרוּ הַחַרְטֻמִּם אֶל פַּרְעֹה: אֶצְבַּע אֱלֹקִים הִוא, וְעַל הַיָּם מָה הוּא אוֹמֵר? וַיַּרְא יִשְׂרָאֵל אֶת־הַיָּד הַגְּדֹלָה אֲשֶׁר עָשָׂה ה' בְּמִצְרַיִם, וַיִּירְאוּ הָעָם אֶת־ה', וַיַּאֲמִינוּ בַּה' וּבְמשֶׁה עַבְדוֹ. כַּמָה לָקוּ בְאֶצְבַּע? עֶשֶׂר מַכּוֹת. אֱמוֹר מֵעַתָּה: בְּמִצְרַים לָקוּ עֶשֶׂר מַכּוֹת וְעַל הַיָּם לָקוּ חֲמִשִּׁים מַכּוֹת.
Rabbi Yose Hagelili says, "From where can you [derive] that the Egyptians were struck with ten plagues in Egypt and struck with fifty plagues at the Sea? In Egypt, what does it state? 'Then the magicians said unto Pharaoh: ‘This is the finger of God' (Exodus 8:15). And at the Sea, what does it state? 'And Israel saw the Lord's great hand that he used upon the Egyptians, and the people feared the Lord; and they believed in the Lord, and in Moshe, His servant' (Exodus 14:31). How many were they struck with with the finger? Ten plagues. You can say from here that in Egypt, they were struck with ten plagues and at the Sea, they were struck with fifty plagues."
וּפַרְעֹ֖ה הִקְרִ֑יב וַיִּשְׂאוּ֩ בְנֵֽי־יִשְׂרָאֵ֨ל אֶת־עֵינֵיהֶ֜ם וְהִנֵּ֥ה מִצְרַ֣יִם ׀ נֹסֵ֣עַ אַחֲרֵיהֶ֗ם וַיִּֽירְאוּ֙ מְאֹ֔ד וַיִּצְעֲק֥וּ בְנֵֽי־יִשְׂרָאֵ֖ל אֶל־ה'׃
וַיֹּאמְרוּ֮ אֶל־מֹשֶׁה֒ הֲֽמִבְּלִ֤י אֵין־קְבָרִים֙ בְּמִצְרַ֔יִם לְקַחְתָּ֖נוּ לָמ֣וּת בַּמִּדְבָּ֑ר מַה־זֹּאת֙ עָשִׂ֣יתָ לָּ֔נוּ לְהוֹצִיאָ֖נוּ מִמִּצְרָֽיִם׃
הֲלֹא־זֶ֣ה הַדָּבָ֗ר אֲשֶׁר֩ דִּבַּ֨רְנוּ אֵלֶ֤יךָ בְמִצְרַ֙יִם֙ לֵאמֹ֔ר חֲדַ֥ל מִמֶּ֖נּוּ וְנַֽעַבְדָ֣ה אֶת־מִצְרָ֑יִם כִּ֣י ט֥וֹב לָ֙נוּ֙ עֲבֹ֣ד אֶת־מִצְרַ֔יִם מִמֻּתֵ֖נוּ בַּמִּדְבָּֽר׃
וַיֹּ֨אמֶר מֹשֶׁ֣ה אֶל־הָעָם֮ אַל־תִּירָ֒אוּ֒ הִֽתְיַצְּב֗וּ וּרְאוּ֙ אֶת־יְשׁוּעַ֣ת ה' אֲשֶׁר־יַעֲשֶׂ֥ה לָכֶ֖ם הַיּ֑וֹם כִּ֗י אֲשֶׁ֨ר רְאִיתֶ֤ם אֶת־מִצְרַ֙יִם֙ הַיּ֔וֹם לֹ֥א תֹסִ֛פוּ לִרְאֹתָ֥ם ע֖וֹד עַד־עוֹלָֽם׃
ה' יִלָּחֵ֣ם לָכֶ֑ם וְאַתֶּ֖ם תַּחֲרִשֽׁוּן׃
וַיֹּ֤אמֶר ה' אֶל־מֹשֶׁ֔ה מַה־תִּצְעַ֖ק אֵלָ֑י דַּבֵּ֥ר אֶל־בְּנֵי־יִשְׂרָאֵ֖ל וְיִסָּֽעוּ׃
As Pharaoh drew near, the Israelites caught sight of the Egyptians advancing upon them. Greatly frightened, the Israelites cried out to ה'.
And they said to Moses, “Was it for want of graves in Egypt that you brought us to die in the wilderness? What have you done to us, taking us out of Egypt?
Is this not the very thing we told you in Egypt, saying, ‘Let us be, and we will serve the Egyptians, for it is better for us to serve the Egyptians than to die in the wilderness’?”
But Moses said to the people, “Have no fear! Stand by, and witness the deliverance which ה' will work for you today; for the Egyptians whom you see today you will never see again.
ה' will battle for you; you hold your peace!”
Then ה' said to Moses, “Why do you cry out to Me? Tell the Israelites to go forward.
88. It is written, "Then Jonah prayed to Hashem his Elohim from the fish's belly," to the place to which he was bound, THE ASPECT OF MALCHUT. This is understood from the words, "Hashem his Elohim." It is not written, 'Then he prayed to Hashem' and nothing more, but "Hashem his Elohim,". Here also, "And Hashem said to Moses, 'Why do you cry to Me?'" "...To Me, davka.
Johnah in the fish was in a place of helplessness and faith. Although Israel prayed like that on the seh, Hashem tells them that they should be taking actions instead.
דבר אל בני ישראל ויסעו. ויסעו מלאסגאה מלין, לאו עידנא דצלותא השתא. ויסעו, וכי לאן אתר פקד לון דינטלון, דהא על ימא הוו שראן. אלא אהדר לעילא, דכתיב מה תצעק אלי, דהא כלהו באתר דא קיימי. וע"ד ויסעו, ינטלון מן דא, דלאו עדנא הוא אלא בעתיקא תלייא מלתא
89. "Speak to the children of Yisrael, that they go forward" (Shemot 14:15), MEANING that they should go forward and refrain from speaking excessively, because now is not a time for prayer. "That they go forward." To which place did He command them to go, seeing that they were camping by the sea? It refers to the above, as it is written, "Why do you cry to Me?". They all stood in this place. Therefore, he said, "that they go forward," that the children of Yisrael should go forth. For now is not the time, but on it depends on travelling.
Place, "makom" is a metaphor for a state of mind or mode of behavior.
וה'' הולך לפניהם יומם. קודשא בריך הוא, ובית דיניה. אמר רבי יצחק, היינו דתנינן, שכינתא באבהתא נטלא. הולך לפניהם יומם: דא אברהם. בעמוד ענן: דא יצחק. לנחותם הדרך: דא יעקב. דכתיב ביה ויעקב הלך לדרכו. ולילה בעמוד אש להאיר להם: דא דוד מלכא.
52. "And Hashem went before them by day." " the Holy One, blessed be He, and His court of law. Rabbi Yitzchak said, We learned that the Shechinah travels with the Patriarchs, BECAUSE "went before them by day," is Abraham, "in a pillar of a cloud," is Isaac, and "to lead them the way," is Jacob, of whom it is written, "And Jacob went on his way" (Beresheet 32:2). "By night in a pillar of fire, to give them light" is King David.
The coud represents the zechut, merit of their forefathers. Good things that they inherited. Before the sea split, they were following it, dependant on it like in Egypt. However, in preparation for the crossing of the sea, the cloud moves behind them, implyting that Hashem is supporting their actions and acting through them.
Each forefather represents a different type of virtuous behavior: Abraham is G'milut Chasadim, Isaac is Discipline, Jacob is intelligence, David is faith. David's inaction and lack of certainty is why his mode is highlighted at night.
53. They are all the holy Chariot of above. In order that Yisrael should be perfect in everything and that the Patriarchs should see their redemption, as it is written, "And I will also surely bring you up" (Beresheet 46:4) with the Chariot, and, "And Hashem went...that they might go by day and by night."
Why did they travel day and night? Let them walk by day, and not by night like people who are fleeing. If the Holy One, blessed be He, guarded them, why did they march day and night?
So they should be complete with everything, because there is no completeness unless day is with night
The Zohar here is essentially saying that the 'pshat doesn't work here, and therefore the real meaning of the story is as a metaphor.
Bar Kappara taught: The handiwork of the righteous is greater than the creation of heaven and earth, as with regard to the creation of heaven and earth it is written: “My hand also has laid the foundation of the earth, and My right hand has spanned the heavens” (Isaiah 48:13). There, hand is written in the singular. Whereas with regard to the handiwork of the righteous it is written: “The place which You have made for Yourself to dwell in, Lord, the Sanctuary, Lord, which your hands have established” (Exodus 15:17). The reference is to the Temple, which is the handiwork of man, and hand is written in the plural.