Midrash sa Isaias 43:3: Mekhilta DeRabbi Yishmael, Shemot Rabbah, Aggadat Bereshit & Midrash Tehillim

Beloved is Israel for whose souls the Holy One Blessed be He has given the nations as kofer, as it is written (Isaiah 43:3) "I gave Egypt as kofer for you." Why? (Ibid. 4) "Because you were honored in My eyes, you were honored and I loved you, and I placed a man in your place and nations in place of your souls."

Another interpretation: “Rise early in the morning” – the Holy One blessed be He said to Moses: ‘This wicked one hardened his heart during the first three. The fourth plague is more severe than the previous ones; go and forewarn him that he should let My people go so the plague will not come upon him.’
“For, if you do not let My people go, behold, I will send swarms upon you, upon your servants, upon your people, and into your houses; and the houses of the Egyptians will be full of swarms, and also the ground on which they are. I will distinguish on that day the land of Goshen, in which My people dwell, that no swarms will be there; so that you will know that I am the Lord in the midst of the earth” (Exodus 8:17–18).
“For, if you do not let My people go, behold, I will send…upon you…” – from where did they come upon them? Some say from above and some say from below. Rabbi Akiva says: From above and from below. Rabbi Shimon ben Lakish said: The Holy One blessed be He said to them: ‘You made many multitudes over My children; I, too, will make upon you many multitudes of birds of the heavens and beasts of the land,’ as it is stated: “Behold, I will send swarms upon you” – beasts and birds intermingled. However, in the land of Goshen, in which Israel was residing, there were no swarms, as it is stated: “I will distinguish on that day the land of Goshen.” Rabbi Ami says: It is like a person who says to another: ‘So-and-so will not be included in this penalty, as his patron, so-and-so, is standing over him.’³He is protecting them.
“I will place a division between My people and your people, tomorrow this sign will be” (Exodus 8:19).
“I will place a division between My people [and your people]” – this teaches that Israel was fit to be afflicted with this plague, but the Holy One blessed be He placed the Egyptians as their ransom. In the future, too, the Holy One blessed be He will bring (ancient)⁴This word, which appears in some editions, was added by the non-Jewish censor. idolaters and cast them into Gehenna in place of Israel, as it is stated: “For I am the Lord your God, Holy One of Israel, your Savior; I gave Egypt as your ransom, Kush and Seva in your stead” (Isaiah 43:3).

[3] Alternative interpretation: "After these events, what is written above the matter? 'And Abraham heard that his brother was taken captive'." (Genesis 14:14). And although his brother was Lot, after all the strife that they had, as it says "And there was strife between the herdsmen of Abram's cattle and the herdsmen of Lot's cattle" (Genesis 13:7), Abram still referred to Lot as his brother, as it says "For we are brothers" (Genesis 13:8). "And he armed his trained servants" (Genesis 14:14). From here we learn that Abram took silver, gold, and jewelry and adorned them, and said to them, "We are going to war to save Lot. Do not focus on wealth. If you are going for the sake of silver and gold, there is plenty before you." As it says, "And he armed his trained servants." And "armed" can only mean adorned with silver and gold, as it says "Her wings are covered with silver, and her pinions with yellow gold" (Psalms 68:14). Alternatively, "armed" means empty-handed, as it is written in the Torah, "Who is the man that is fearful and soft-heated?" (Deuteronomy 20:8), Abraham acted similarly. He said to his troops, "You are going out to war, but anyone who has sins in his hand and is afraid of his deeds should not go out with us." When all those men heard this, anyone who knew in his heart that he had sinned did not go out with Abraham, and they all turned back except for Eliezer who was righteous. Then, God said to Abraham, "He will go with you, and I will give him the strength of 318 men, so it will be as if all of them went out with you." Similarly, Eliezer's strength was equivalent to 318 men. And Abraham pursued [the kings] as far as Dan (Genesis 14:14). Why did he pursue them all the way to Dan? Our sages said that there are two things that are punished, those who plant a tree in the Sabbatical year and those who sell the produce of the Sabbatical year. Similarly, Abraham punished them before and after the prohibition [against such actions] came into effect. And how did he do so before [the prohibition was enacted]? Until now, when Jeroboam, the son of Nebat, would establish an idol in Dan, as it is said, "And he put one in Beth-El and the other he placed in Dan" (1 Kings 12:29). Abraham had already arrived at that place and did not pursue them any further, as it is written, "And he pursued them as far as Dan, and he recovered all the goods" (Genesis 14:15).. What did he see in pursuing them to Dan? Our sages said two things strike those who are before and after, as in the case of the "sabbatical year" where one who plants before it and after it is liable. Similarly, Abraham pursued them before and after, but how did he pursue them until now when Jeroboam son of Nebat set up a sanctuary in Dan, as it says, "And he placed the one in Bethel [and the other he put in Dan]" (1 Kings 12:29)? Abraham had already reached that place and did not pursue them anymore, as it says, "And he pursued them to Dan and he divided himself against them by night" (Genesis 14:15). The Holy One, blessed be He, did this for Abraham, as it says, "And it came to pass that at midnight the Lord smote" (Exodus 12:29), "And he brought back all the goods" (Genesis 14:16), "Then the king of Sodom went out to meet him" (Genesis 14:17). When the king of Sodom saw Abraham coming to pursue him, he was playing with him, as it says, "All those who see me will mock me" (Psalms 22:8). This was the king who went out to pursue sixteen kings and their armies. When he returned safely, he said, "Let them pass in peace" (Isaiah 43:3). "Then the king of Sodom went out to meet him" (Genesis 14:17), and said to him, "Give me the persons" (Genesis 14:21). Abraham immediately swore to him, as it says, "I have lifted my hand" (Genesis 14:22), and lifting one's hand is an oath, as it says, "He raised his right hand and his left hand to heaven [and swore by the living God]" (Daniel 12:7). "If from a thread" (Genesis 14:23), why did the Holy One, blessed be He, promise to tithe me, as it says, "And I will bless those who bless you" (Genesis 12:3)? "And I will curse him who curses you" (Genesis 12:3). I am poorer than you. You should say, "I enriched you." "If from a thread" (Genesis 14:23). The Holy One, blessed be He, said to him, "You said, 'If from a thread.' I will give your children a thread of righteousness that will encompass them, just as the sages have explained." "I give your children the commandment of tzitzit which is made of thread, as it says 'they shall make for themselves fringes' (Numbers 15:38). You said until shoelace, I give your children the commandment of shoe removal, as it says 'he shall remove his shoe' (Deuteronomy 25:9). Additionally, I give your children the merit of the Passover commandment, as it says 'you shall eat it with your loins girded, your sandals on your feet' (Exodus 12:11). If you said from thread, I praise your children with the thread, as it says 'your hair is like a flock of goats' (Song of Songs 4:2). Moreover, in the merit of this, I punish their enemies, as it says 'over Edom I cast my shoe' (Psalms 60:9). If you said until shoelace, I praise your children with their footwear, as it says 'how beautiful are your steps in sandals' (Song of Songs 7:1). You have rejected the reward of flesh and blood, see the reward that is prepared for you, as it says 'your reward is very great' (Genesis 15:1)."