Talmud zu Pirkei Avot 5:4

Abraham our forefather was tested with ten trials before the Holy Blessed One, and he emerged from each one complete.
They are as follows: Two when God said to him, “Go forth!” Two with his two sons. Two with his two wives. One with the war of the kings. One at the Covenant of the Parts. One in Ur Kasdim. One with circumcision. (The Covenant of the Parts.) And why so many? So that when Abraham our forefather comes to take his reward, the angels will say: More than us, more than anyone, Abraham deserves his reward, as it says (Ecclesiastes 9:7), “Go, eat your bread with joy, and drink your wine with a happy heart.”
Because Abraham was tested with ten trials, and emerged from each one complete, the Holy Blessed One performed ten miracles for his children in Egypt, and brought ten plagues, and performed ten more miracles at the sea, and brought ten more plagues upon the Egyptians at the sea.
The Egyptians roared at the top of their lungs, and so the Holy Blessed One thundered back across the sea, as it says (Job 37:5), “God thunders marvelously with His voice.” The Egyptians came to the sea with bows and arrows, and so the Holy Blessed One appeared before them with a bow and arrow, as it says (Habakkuk 3:9), “Bared and ready is Your bow,” and (Psalms 18:15), “He sent forth His arrows and scattered them….” The Egyptians came to the sea with swords, so the Holy Blessed One came upon them with swords (and mercy), as it says (ibid.), “He sent forth His arrows and scattered them; He discharged lightning and routed them.” And lighting always means a sword, as it says (Ezekiel 21:14–15), “The sword, the sword has been sharpened and polished, sharpened in order to slaughter, so that it sparkles like lightning.” The Egyptians came proudly with shield and armor, and so the Holy Blessed One did the same, as it says (Psalms 35:2), “Grab shield and armor and rise to my defense.” The Egyptians came with spears, and so did the Holy Blessed One, as it says (Habakkuk 3:11), “Your flashing spear in brilliance.” The Egyptians came with rocks and slings, and the Holy Blessed One outdid them with hailstones, as it says (Psalms 18:13), “(Out of the brilliance before Him,) hail and fiery coals pierced His clouds.”
When our ancestors stood at the sea, Moses said to them: Arise and cross! They said to him: We will not cross until the sea begins to split open. So Moses took his staff and struck the sea, and it began to split open, as it says (Habakkuk 3:14), “You will split open the heads of his warriors with your staff.” Moses said to them: Arise and cross! They said to him: We will not cross until the sea becomes like a valley before us. So Moses struck the sea and it became like a valley before them, as it says (Psalms 78:13), “He split the sea and passed them through,” and (Isaiah 63:14), “Like a beast going down into the valley.” Moses said to them: Arise and cross! They said: We will not cross until it is divided into sections, as it says (Psalms 136:13), “Who divided the Sea of Reeds into sections.” Moses said to them: Arise and cross!. They said: We will not cross until it becomes solid matter. So Moses took his staff and struck the sea, and it became mud, as it says (Habakkuk 3:15), “You led Your horse into the sea, onto solid waters.” Moses said to them: Arise and cross! They said: We will not cross until it becomes a desert. So Moses took his staff and struck the sea, as it says (Psalms 106:9), “He led them through the depths as if it were the desert.” Moses said to them: Arise and cross! They said: We will not cross until it becomes all smashed up into particles. So Moses took his staff and struck the sea, as it says (Psalms 74:13), “You smashed the sea with Your might.” Moses said to them: Arise and cross! They said: We will not cross until it becomes a bed of rocks. He took his staff and struck the sea, as it says (there), “You broke the heads of crocodiles on the water.” And they could not be broken like this except on rocks. Moses said to them: Arise and cross! They said: We will not cross until it becomes dry land. So Moses took his staff and struck the sea, as it says (Psalms 66:6), “He turned the sea into dry land,” and (Exodus 14:29), “And the children of Israel walked on dry land in the midst of the sea.” Moses said to them: Arise and cross! They said: We will not cross until it becomes walls. So Moses took his staff and struck the sea, as it says (Exodus 14:22), “And the water became a wall for them, on their right and on their left.” Moses said to them: Arise and cross! They said: We will not cross until goatskins (nodot) [to drink from] appear before us. So Moses took his staff and struck the sea, as it says (Exodus 15:8), “[The walls] stood like a stack (ned) of flowing water.” (And where do we learn that between the sections, fire came down and, as it says [Isaiah 64:1], “Like fire kindles brushwood, and fire boils water to announce Your name to Your antagonists”?) And so the goatskins would draw oil and honey into the mouths of the babies, who would nurse from them, as it says (Deuteronomy 32:13), “He nursed him with honey from the rock.” And some say that fresh water flowed from the sea, and they would drink it between the sections of the sea, since seawater is usually salty, for it says, “flowing,” which always means sweet, as it says (Song of Songs 4:15), “A well of fresh water, flowing from the Lebanon.” And the Clouds of Glory were above them, so that the sun would not oppress them. And this is how the Israelites crossed the water, in order that they would feel no pain.
Rabbi Eliezer would say: The sea depths were arched over them from above, and the Israelites crossed through, so that they would feel no pain. Rabbi Elazar and Rabbi Shimon would say: The upper waters and the lower waters tossed the Egyptians, as it says (Exodus 14:27), “The Eternal tossed the Egyptians into the sea.”