מדרש אויף שיר השירים 8:1

“If only you were like a brother to me, who suckled the breasts of my mother. I would find you outside; I would kiss you, yet they would not despise me” (Song of Songs 8:1).
“If only you were like a brother to me” – like what brother? Like Cain to Abel? Cain killed Abel, as it is stated: “Cain arose against Abel his brother, and killed him” (Genesis 4:8). Rather, like Ishmael to Isaac? Ishmael hated Isaac. Rather, like Esau to Jacob? But it is stated: “Esau hated Jacob” (Genesis 27:41). Rather, like Joseph’s brothers to Joseph? They hated him, as it is stated: “His brothers were jealous of him” (Genesis 37:11). Like what brother? “One who suckled the breasts of my mother” – that is to say like Joseph to Benjamin, who loved him wholeheartedly, as it is stated: “Joseph saw Benjamin with them” (Genesis 43:16).¹As the story unfolds, the verse states that Joseph wept when he saw Benjamin (Genesis 43:30).
“I would find you outside; I would kiss you”; “outside” – this is the wilderness, which is outside the settled area. “I would kiss you” – regarding two brothers who kissed each other, and these are Moses and Aaron, as it is stated: “He went, and he met him at the mountain of God, and he kissed him” (Exodus 4:27).
“They would not despise me” – Rabbi Pinḥas said: There was an incident involving two siblings, one of whom was in Meron and one in Gush Ḥalav. The house of the one who lived in Meron caught fire. His sister from Gush Ḥalav came and began hugging, embracing, and kissing him, and saying: This does not demean me, as my brother was in dire straits and was delivered from them.

“The Lord said to Aaron: Go toward Moses to the wilderness. He went, and he met him at the mountain of God and he kissed him” (Exodus 4:27).
“The Lord said to Aaron: Go toward Moses to the wilderness” – that is what is written: “If only you were as my brother [who nursed from the breasts of my mother; I would find you outside, I would kiss you]” (Song of Songs 8:1). Regarding which brother is the verse speaking? If you say it is regarding Cain, but is it not written: “Cain rose against his brother Abel and killed him”? If you say it is like Ishmael to Isaac, did we not learn: Ishmael hates Isaac? If you say it is like Esau to Jacob, is it not written: “Esau hated Jacob” (Genesis 27:41)? If you say it is like Joseph’s brothers, but is it not written: “They hated him” (Genesis 37:4), and it is written: “His brothers envied him” (Genesis 37:11). Rather, it is like Joseph to Benjamin, “who nursed from the breasts of my mother” (Song of Songs 8:1),¹Joseph and Benjamin were from the same mother, Rachel, whereas their other brothers were not sons of Rachel. [and] like Moses to Aaron, as it is stated: “He went, and he met him at the mountain of God and he kissed him.”
Our Rabbis, of blessed memory, said: All kisses are indecent except for three: The kiss of greatness, the kiss of separation, and the kiss of reunion. The kiss of greatness, as it is stated: “Samuel took the vial of oil, and poured it upon his head, and kissed him” (I Samuel 10:1); the kiss of separation: “Orpa kissed her mother-in-law” (Ruth 1:14); the kiss of reunion, as it is stated: “He went, and he met him at the mountain of God and he kissed him.”
Some say: Even a kiss of closeness is not disgraceful, as it is stated: “Jacob kissed Rachel” (Genesis 29:11), who was his relative. Rabbi Pinḥas said: There was an incident involving a brother and a sister, one of whom was in Gush Ḥalav and one of whom was in Beit Maron. The house in Gush Ḥalav caught fire. His sister came from Beit Maron and fell upon him and was hugging him and kissing him. She said: ‘I am not accustomed to come to you [and to kiss you], but I was afraid, as you are my brother and were in distress, and you emerged from it.’
“I would find you outside, I would kiss you” (Song of Songs 8:1) – where outside? It is in the wilderness, where the brothers, Moses and Aaron, kissed each other.

"If only you were like my brother, who nursed [at my mother's breast]" (Songs 8:1). Like which "brother" [does this verse refer]? Like Cain to Abel? Cain killed Abel. Like Ishmael to Isaac? Ishmael hates Isaac. Like Esau to Jacob? Esau hates Jacob. Like the brothers of Joseph to Joseph? The brothers of Joeph hate Joseph. Rather, like Joseph to his brothers. You find that after all the evil that they did to him, what is written about it? "And now, do not be afraid. I will sustain you and your little ones. And he comforted them and spoke to their hearts" (Gen. 50:21). Said Rabbi Simlai, he said to them, "You are the head and I am the body. If the head is taken away, what good is the body?" Another interpretation: He said to them, "You shall be likened to the dust of the earth, and like the sand of the sea, and like the stars of the heavens. Behold, I am going and I am waging war for them (i.e., the Egyptians). If I can do so for them, behold, I can do so for you, and if I cannot do so for them, I could not do so for you." Another interpretation: He said to them, "‘Shall I become an adversary to my father; my father begets and I bury?" Another interpretation: He said, "Shall I become an adversary to the Holy One Blessed be He? The Holy One blesses and I diminish?" Another interpretation: He said to them, "You conduct yourselves according to the order of the world, twelve hours during the day and twelve hours during the night, twelve months, twelve constellations of the zodiac, twelve tribes. Is it possible for me to abolish the conduct of the order of the world?" Another interpretation: He said to them, "Before you descended here, the Egyptians were treating me like a slave. Once you descended here, they recognized my nobility." Another version: "He said to them, "If I kill you now, the Egyptians would say, "He saw a group of young men, and he said, 'Perhaps they are my brethren.' You should know that it is so, that after time had passed, he found some pretext and he killed them." Another interpretation: He said to them, "If I kill you now, the Egyptians would say, 'If he did not keep faith with his brothers, would he keep faith with us?'" Therefore, "He comforted them and he spoke to their hearts" (Gen 50:21). And behold these matters may be logically deduced: If regarding Joseph, who spoke kind and comforting words to the hearts of his brothers, and they were comforted, how much more so when the Holy One Blessed be He comes to comfort Jerusalem as one, [and thus it says,] "Comfort, O comfort, my people, says your God" (Is. 40:1).