What is the meaning of "Molich li'Ymin Moshe Zero'a Tif'arto"?
Rashi: Hashem put the Zero'a of His Gevurah to Moshe's right. Whenever Moshe needs His help, His arm is prepared, at his right.
Radak: This tells how He raised them from the sea and how they descended to the sea. Even though it is known, he says so to aggrandize the tale and thank Kel, for it was a great wonder. He put the Zero'a of His glory to Moshe's right; the staff was in his right hand. How could his staff split the sea?! Rather, it was Hashem's arm.
Malbim: The miracles done via Moshe were greater in four ways. (a) They were constant miracles, whenever the faithful shepherd wanted. He brought the miraculous Zero'a to him, to use whenever he wanted. (b) The miracles were not via an angel and intermediary. (The Zero'a was at his right hand, without anything in between.) (c) The miracles were not via Yisrael's merits, rather, Hashem's Ko'ach and desire. Zero'a refers to power to act without help from acts of lower beings. (d) The miracles were not tied to nature. Rather, they were great famous miracles - Tif'arto, to be glorified in the eyes of all.
Why does it say "Boke'a Mayim Mipneihem"?
Radak: It was due to Yisrael, in order that [the Egyptians] will drown in it.
Malbim: It was not only in order to save them. He could have saved them without a miracle like this, rather, in a natural way. Rather, it was to make a permanent name for Himself.
How did He make a permanent name?
Radak: All nations will mention Him for this great matter, and fear Him - "Sham'u Amim Yirgazun" (Shemos 15:14)). He did not need to move Yisrael to the other end, for they left from the same end that they entered. He did so to show His great hand, and that everything is in His ability, even to change the nature of the elements. This is glory for Him and a permanent name. He shows all this via Moshe and His nation Yisrael, amidst His love of them.
