Les Proverbes 17:17 Midrash : Shemot Rabbah, Mekhilta DeRabbi Yishmael, Ein Yaakov (Glick Edition) & Mekhilta DeRabbi Shimon Ben Yochai

Another interpretation: “Moses went” – that is what is written: “A friend loves at all times, and a brother is born for adversity” (Proverbs 17:17). Who is “a friend loves”? This is Yitro, who accepted Moses when he was fleeing from Pharaoh. From here you learn that one who accepts upon himself to perform a mitzva, that mitzva does not cease from his household. Yitro’s mitzva was that he accepted into his house a deliverer who fled from an enemy. From his house, one emerged who accepted an enemy who fled from a deliverer, and killed him. Who is that? Sisera, as it is stated: “Sisera fled on foot to the tent of Yael, wife of Ḥever the Kenite” (Judges 4:17), and it is written: “The children of the Kenite, father-in-law of Moses” (Judges 1:16). Therefore, it says: “A brother is born for adversity” – because Yitro loved Moses and was his friend, therefore his descendants became brethren to Israel in their time of trouble, and Yael killed Sisera.
When the Holy One blessed be He said to him: “Go now, and I will send you to Pharaoh” (Exodus 3:10), he said to Him: ‘Master of the world, I am not able to do so, because Yitro accepted me and opened his house to me and I am like a son to him. One who opens his door to another, [the latter] owes him his life.’ Likewise, you find regarding Elijah when he went to the widow from Tzarefat, her son died. He began pleading and saying: “Have You brought evil even upon the widow with whom I lodge, to kill her son?”³Due to Elijah’s debt of gratitude toward the widow, he risked his life on her behalf by praying impertinently for her son’s revival. Similarly, Moses risked his life for Yitro by not undertaking God’s mission without Yitro’s permission (Etz Yosef). (I Kings 17:20). And it is written: “The Lord heeded the voice of Elijah, and the soul of the child was restored” (I Kings 17:22).
Moreover, anyone who opens his door to another, [the latter] is obligated in his honor more than in the honor of his father and mother. You find that at the moment that Elijah was taken from Elisha, and [Elisha] was privileged to take a double portion of his spirit, as it is stated: “Please, let a double portion of your spirit be upon me” (II Kings 2:9), he should have gone to his father and mother and revived them as he did the son of his hostess.⁴See II Kings, chap. 4. Likewise, Elijah should have revived his ancestors, as he did the son of the [widow from] Tzarefat, but he risked his life [only] on behalf of his hostess. That is why Moses said before the Holy One blessed be He: ‘Yitro accepted me and treated me with respect; I will go only with his permission.’ Therefore, it is written: “Moses went and returned to Yeter his father-in-law.”

R. Chanina b. Chachinai says: Have I not had it written (Mishlei 17:17) "A brother is born for (times of) trouble"? I am a brother to Israel in their time of trouble. "Brother" (here) signifies Israel, viz. (Psalms 122:8) "For the sake of My brothers and My friends I will speak for peace in you (Jerusalem)."

R. Abahu used to lecture about the three kings. Becoming sick, he decided not to lecture about them any more. But after he was cured (Ib. b.) he lectured about them as before, and to the question of his disciples: "Have you not determined not to lecture any more about them?" he answered: "Did they then repent that I shall do so?" R. Ashi appointed a time for lecturing about the three kings, and said: "On the morrow we will begin our lecture about our colleague Manasseh." The latter then appeared to him in a dream, and said to him: "You call me a colleague and a colleague of your father? Answer me the question: "Where must one begin to cut the bread by the benediction of the hamotzi?" And he said: "I do not know." Manasseh then rejoined: "If you do not know the answer to even this which I question you, how can you call me a colleague." R. Ashi said to him: "Teach this to me, and tomorrow I will proclaim it in your name in the college." And he said: "From that part where it begins to bake when in the oven." Said R. Ashi again: "If you are so wise, why did you worship idols?" And Manasseh answered: "If you would have been living at that time you would have lifted up the edges of your dress [that they shall not impede you] to run after them to worship them." On the morrow said R. Ashi to the Rabbis: "Let us lecture about the great men. Achab — means Ach, a cause of grief to Heaven, and ab, a father (friend) of idolatry (I Kin. 16, 31) And it came to pass, as if it had been a light thing for him to walk in the sins of Jeroboam." R. Jochanan said: "The minor sins committed by Achab were greater than the grave sins that Jeroboam committed, and why then does the Scripture make Achab dependent on Jeroboam? Because he initiated corruption." (Hos. 12, 12) Their altars also are as stone heaps. R. Jochanan said: "There was not one heap in the land of Israel upon which Achab had not placed an idol and bowed himself down to it."