Midrash sa Exodo 2:14: Shemot Rabbah, Devarim Rabbah, Midrash Tanchuma Buber & Mekhilta DeRabbi Yishmael

“He turned this way and that and saw that there was no man; he smote the Egyptian and concealed him in the sand” (Exodus 2:12).
“He saw that there was no man,” because he was deserving of death. Rabbi Yehuda says: There was no man who would be zealous on behalf of the Holy One blessed be He, and kill him. Rabbi Neḥemya says: He saw that there was no one who would invoke the name of God and kill him. The Rabbis say: He saw that there was no expectation that righteous people would emerge from him or from his descendants until the end of all the generations. When Moses saw this, he consulted with the angels and said to them: ‘Is this one liable for execution?’ They said: ‘Yes.’ That is what is written: “He saw that there was no man” – who would speak in his favor.
“He smote the Egyptian.” With what did he kill him? Rabbi Evyatar said: He struck him with a fist. Some say: He took a mortar rake and removed his brain. The Rabbis say: He invoked the name of God and killed him, as it is stated; “Do you propose [omer] to kill me [as you killed the Egyptian?]” (Exodus 2:14).
“He concealed him in the sand” as there was no one there other than Israelites. He concealed him before Israel, who were likened to sand. He said to them: ‘You were likened to sand; just as sand, a person takes it from here and places it there and no sound is heard, so too, this matter will remain concealed among you and will not be heard.’ Indeed, you find that the matter was heard only by means of the Hebrews, as it is stated: “He went out on the second day and behold, two Hebrew men were fighting [nitzim]; [he said to the wicked one: why do you strike your counterpart?]” (Exodus 2:13). These are Datan and Aviram, and it called them nitzim after their end.⁶⁴“They are Datan and Aviram…who agitated [hitzu] against Moses…when they agitated [behatzotam] against the Lord” (Numbers 26:9). It was they who said this matter, it was they who left over some of the manna. It was they who said: “Let us appoint a leader and return to Egypt” (Numbers 14:4). And it was they who agitated at the Red Sea.
Alternatively, [they are called] nitzim because they intended to kill one another, as it is said: “If men fight together” (Deuteronomy 25:11), and Rabbi Elazar said: The verse is referring to a fight to the death.
“He said to the wicked one: Why do you strike your counterpart?” Why did you strike is not stated, but rather “why do you strike.” From here it is derived that from the moment that a person raises his hand against another, even if he does not strike him, he is called wicked. “Your counterpart,” who is wicked like you are; this teaches both of them were wicked.

“He said: Who appointed you a ruler and judge over us? Do you propose to kill me as you killed the Egyptian? Moses was frightened and said: Indeed, the matter is known” (Exodus 2:14).
“Who appointed you a ruler [and judge [ish sar veshofet] over us?]” – Rabbi Yehuda says: Moses was twenty years old at that time. They said to him: ‘You are not yet eligible to be a ruler and a judge over us, because [only] one who is forty years old has understanding’ (Avot 5:25). Rabbi Neḥemya says that he was forty years old. They said to him: ‘Certainly you are a man [ish], but you are not eligible to be a ruler and a judge [sar veshofet] over us.’ The Rabbis say that they said to him: ‘Aren’t you the son of Yokheved? How do they call you son of Batya? You seek to be a ruler and a judge over us? We will inform about you, what you did to the Egyptian.’
“Do you propose [omer] to kill me?” Do you seek to kill me is not stated, but rather do you omer [literally, say]. From here you learn that he had invoked the ineffable name against the Egyptian, and killed him. When he heard this,⁶⁵When Moses heard the response of the Hebrew man he had rebuked. he feared slander and he said: “Indeed, the matter is known.” Rabbi Yehuda bar Rabbi Shalom [said] in the name of Rabbi Ḥanina the Great, and our Rabbis said in the name of Rabbi Alexandri: Moshe was pondering in his heart and saying: What sin did Israel commit that caused them, more than all the nations, to be enslaved? When he heard his response, he said: ‘There is slander in their midst, how can they be deserving of redemption?’ Therefore he said: “Indeed the matter is known” – now I know the reason for their enslavement.

What did Moses see that led him to devote himself to [designating] the cities of refuge? Rabbi Levi said: One who ate the dish knows its taste. How so? When Moses killed the Egyptian, he went out on the second day and found Datan and Aviram quarreling with one another, as it is stated: “He emerged on the second day, [and behold, two Hebrew men were fighting, and he said to the wicked one: Why do you strike your neighbor?]” (Exodus 2:13). Rabbi Aivu said: This [wicked one] was Datan. [Datan] began demeaning him: “Do you propose to kill me?” (Exodus 2:14). When Pharaoh heard this, he said: ‘How many things have I heard and been silent. Now that he has arrived at bloodshed, apprehend him.’ How did he flee from Pharaoh, as it is written: “Moses fled from Pharaoh” (Exodus 2:15)? Rabbi Yannai said: The executioner came to place the sword on his neck; the sword was blunted on his neck, which turned into marble. Solomon lauded him: “Your neck is like an ivory tower” (Song of Songs 7:5). Rabbi Evyatar said: Moreover, the sword caromed off his neck and it turned onto the executioner. From where is this derived? As it is stated: “He delivered me from the sword of Pharaoh” (Exodus 18:4) – Moses said: The Holy One blessed be He delivered me but not the executioner. Bar Kappara said: An angel descended in Moses’s image and facilitated his flight. They thought the angel was Moses. Rabbi Yehoshua said: See the miracles that the Holy One blessed be He performed on behalf of Moses: All of Pharaoh’s scholars, some of them became mute, some of them became deaf, some of them became blind, and Moses fled and they did not see him. Know that when the Holy One blessed be He sought to send him on a mission, he began hesitating. The Holy One blessed be He said to him: ‘Do you not recall what I did to Pharaoh’s scholars,’ as it is stated: “The Lord said to him: Who gives a mouth to a person, [or who renders one mute, or deaf, or sighted, or blind]” (Exodus 4:11)? ‘At that time I stood with you, and now, will I not stand with you?’
Rabbi Yitzḥak said: Come and see that the actions of the Holy One blessed be He are not like the actions of mortal man. The way of the world is that mortal man procures himself a patron who protects him. If he is apprehended and placed on trial, [his friends] go and find his patron and say to him: ‘A member of your household has been apprehended.’ He says to them: ‘I will protect him.’ But if he is taken out to be executed, where is he and where is his patron? But the Holy One blessed be He is not so. The ministering angels said to Him: ‘A member of your household, Moses, has been apprehended.’ He said to them: ‘I will protect him.’ They said to Him: ‘He is standing before Pharaoh; his sentence is being read; he is being taken out for execution.’ He said to them: ‘I will protect him.’ He was taken out for execution, and the Holy One blessed be He delivered him. From where is this derived? As it is stated: “He delivered me from the sword of Pharaoh” (Exodus 18:4).
Another matter: A person who has a patron and he is apprehended in his sin and cast to a place of beasts – where is he and where is his patron? Daniel was cast into the lions’ den, and the Holy One blessed be He delivered him. From where is this derived? As it is stated: “My God sent His angel, and he shut the lions’ mouths” (Daniel 6:23).
Another matter: If a person procures himself a patron and performs a sin, and the judge decrees upon him that he is to be burned, where is he and where is his patron? But the Holy One blessed be He is not so. The ministering angels said before the Holy One blessed be He: ‘A member of Your household, Abraham, was apprehended.’ He said to them: ‘I will protect him.’ They said to Him: ‘He is standing before Amrafel, his sentence is being read, and he is about to be burned.’ He said to them: ‘I will protect him.’ [Abraham] was cast into the fiery furnace, and the Holy One blessed be He descended and delivered him. From where is this derived? As it is stated: “He said to him: I am the Lord, who took you out of Ur of the Chaldeans” (Genesis 15:7).⁶³The word Ur can also be translated “fire,” as in Isaiah 47:14.
Another matter: If a person procures himself a patron and he is apprehended in his sin, and the judge decrees upon him that he is to be cast into the sea, where is he and where is his patron? But the Holy One blessed be He is not so. Jonah was cast into the sea, and the Holy One blessed be He delivered him. From where is this derived? As it is stated: “The Lord spoke to the fish, and it spewed Jonah [upon the dry land]” (Jonah 2:11).
Another matter: “Then Moses designated” – Rabbi Aivu said: When Moses fled, he began to sing a song [of praise], as it is stated: “And he settled in the land of Midian, and he sat at the well” (Exodus 2:15). Just as Israel sang a song at the well,⁶⁴See Numbers 21:17. so Moses sang a song at the well. Rabbi Levi said: [He sang] because the portion of the murderer in the city of refuge took effect through him.⁶⁵The portion begins: “Then [az] Moses designated,” indicating that he sang, just as the song at the sea begins: “Then [az] Moses and the children of Israel sang” (Exodus 15:1). The reason he sang is that he himself had been rescued after having killed someone.