Midrash su Isaia 63:12

..."And the waters were a wall for them" Made them as a type of wall. "On their right and on their left" On their right due to the merit of the Torah that they would in the future receive through the right, as it is said "From His right, a fiery law to them" (Deut. 33:2). And on their left: this is prayer.

"And you, raise your staff" (Exodus 14:15) Moses said before the Holy One Blessed Be He, "You say to me that I will split the sea and I will make the sea dry land, but is it not written, 'that I have placed sand as the boundary of the sea' (Jeremiah 5:22)? And behold, you have sworn that you will not split ever!" Rabbi Eliezer ha Kappar said: Moses said to Him"Not so, for you have said that the sea will not be made dry land, as was said 'that I have placed sand as the boundary of the sea' and it is written, 'And who shut up the sea with doors' (Job 38:8)!" The Holy One Blessed Be He said to him, "You have not read the Torah from the beginning. What is written? 'And God said, let the waters be gathered' (Genesis 1:9). I am the one who placed a condition on it - such I placed a condition from the beginning that I would split it, as was said, 'the sea returned according to its condition at the approach of morning' (Exodus 24:27) [reading l'eitano - "to its strength" as liteinao "according to its condition"]" Immediately, Moses listened to God and went to split the sea, but when he went to divide the sea, it would not accept from him to split. The sea said to him, "I should split before you? I am greater than you! I was created on the third day, and you were created on the sixth day!" When Moses heard this, he went and said to the Holy One Blessed Be He, "The sea doesn't want to be split." What did the Holy One Blessed Be He do? He put His right hand on the the right hand of Moses, as it is said, "who caused [His glorious arm] to go at the right hand of Moses [dividing the waters before them to make Himself an eternal name]" (Isaiah 63:12) Immediately, it saw the Holy One Blessed Be He and fled, as was said, "the sea saw and fled" (Psalms 114:3). What did it see? It saw none other than the Holy One Blessed Be He who gave His right hand upon Moses, and it could not delay, but split immediately. Moses said, "Because of what do you flee?" The sea said to him, "Because of the God of Jacob. (Psalms 114:7) Because of the fear of the Holy One Blessed Be He." Immediately when Moses raised his hand against the sea, it was split, as was said, "The waters split" (Exodus 14:21). It does not say, the sea split, but rather the waters split to teach that all the waters that were in all the springs, and the well and in every place were split, as was said, "The waters were split." And so, at the time that they returned, all the waters returned, for such it says, "And the waters returned" (Exodus 14:28). And all these miracles were done through the hand of Moses, as was said, "And Moses extended his hand over the sea" (Exodus 14:21). Therefore, the Holy One Blessed Be He praised him, as was said, "His people remembered the days of old - Moses" (Isaiah 63:11), and it is written [in the next verse]: "who caused [His glorious arm] to go at the right hand of Moses".