Midrash su Deuteronomio 25:18

You find that everything written in praise of Jethro is mentioned to the discredit of Esau. In reference to Esau it is written: They have ravished the women in Zion (Lam. 5:11), but about Jethro it says: And he gave Moses, Zipporah, his daughter (Exod. 2:21). Concerning Esau it is written: Who eat up My people as they eat bread (Ps. 14:4), while of Jethro it is said: Call him that he may eat bread (Exod. 2:20). It is written about Esau: And he feared not God (Deut. 25:18), but about Jethro it is written: And thou shalt provide out of all the people, able men, such as fear God (Exod. 18:21). It is stated about Esau that he abolished the sacrifices (when Rome destroyed the Second Temple), but of Jethro it is said: And Jethro, Moses’ father-in-law, took a burnt-offering and sacrifices (ibid., v. 12). Esau heard of their troubles and attacked them, as it is said: Because of the striving of the children of Israel, and because they tried the Lord (ibid. 17:7), and it is written elsewhere: And Amalek came. However, when Jethro heard about Israel’s goodness, he joined them, as it is said: Now Jethro heard.

(Exodus 17:8) "And Amalek came": This verse is recondite and is explicated by (Iyyov 8:11) "Can the rush grow without swamp? Can grass grow without water?" So, Israel without Torah. And because Israel separated from Torah, therefore, the foe (Amalek) came upon them. For the foe comes only by reason of sin and transgression. Thus, "And Amalek came, etc." R. Elazar Hamodai says: "And Amalek came": Amalek "sneaked" under the edges of the cloud and snatched souls of Israel and killed them, viz. (Devarim 25:18) (Amalek) "who met you on the way … when you were faint and weary and (Amalek) did not fear G d." Others say: This refers to Israel, who (at that time) did not have mitzvoth in their hands.

“Mordekhai told him everything that had befallen him [karahu]” (Esther 4:7). He said to Hatakh: ‘Tell her that the descendant of karahu⁶Amalek, the subject of the verse in Deuteronomy 25:18. has come against you; that is what is written: “That he encountered you [kareḥa] on the way”’ (Deuteronomy 25:18).
Alternatively, “that had befallen him” in a dream, indicating that he reminded her of a dream that he had dreamed along these lines during the second year of the reign of Aḥashverosh. He saw, and behold, a great and powerful earthquake, panic in the world, and fear and trembling for all its residents. And behold, two great serpents each bellowing toward the other and they waged a war, and all the nations of the world fled due to their noise. There was among them a certain small nation, and all the nations attacked the small nation to eliminate any memory of it from the earth. On that day there was darkness for the entire world, and that small nation was very distressed and they cried to God. The serpents were waging war furiously and there was no one to separate between them.
Mordekhai saw, and behold, there was a certain spring of water that passed between these serpents and it separated between them, preventing the war they had been waging. The spring swelled and became a raging stream, like the flow of the Mediterranean Sea, that gradually inundated the land. He saw and the sun shone for the entire land and the world was illuminated. The small nation was elevated, the dominant were lowered, and peace and truth were found throughout the land.
It was from that day forward, Mordekhai kept that dream that he had dreamt, and when Haman was causing him distress, he said to her [Esther] by means of her emissary: ‘This is the dream that I told you in your youth. Now, arise and ask for mercy from the Holy One blessed be He, and come before the king and entreat him on behalf of your people and your family.’