Midrasch zu Schir haSchirim 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.

"God restores my soul" This means that Israel said, God restores my soul with Torah, as it says, "The Torah of Adonai is perfect, restoring the soul" (Psalms 19:18). "God leads me in the paths of mercy"--this means, to manna, to quail, to waters of the well, to clouds of glory; and these are given to me not because I have earned them but "for the sake of God's name." Even as I walk through the valley of the shadow of death, though I walk on the parched land of the wilderness, "I will fear no evil for You are with me," as it says, "Adonai went before them by day in a pillar of cloud (Exodus 13:21). Your rod and your staff, they comfort me: the rod is Your chastisements; the staff, Your Torah.

Another interpretation (of Exod. 4:27): GO INTO THE DESERT TO MEET MOSES. This text is related (to Cant. 8:1): IF ONLY YOU COULD BE TO ME LIKE A BROTHER. Israel is saying to the Holy One: IF ONLY YOU COULD BE TO ME LIKE A BROTHER. Like which brother?¹¹⁰Tanh., Exod. 1:27; Exod. R. 5:1; PRK 16:5; PR 29/30A:6; 29/30B:1. You find that from the beginning of the creation of the world until now brothers have hated each other. Cain hated Abel and killed him, as stated (in Gen. 4:8): CAIN AROSE AGAINST HIS BROTHER ABEL AND MURDERED HIM. Ishmael hated Isaac (rt.: TsHQ), as stated (in Gen. 21:9): WHEN SARAH SAW THE SON WHOM HAGAR THE EGYPTIAN HAD BORNE TO ABRAHAM PLAYING (rt.: TsHQ). Now PLAYING can only mean that he desired to kill him, as stated (in II Sam. 2:14): PLEASE LET THE YOUNG MEN ARISE AND PLAY BEFORE US.¹¹¹The result of their “playing” was that they all killed each other. See above, Gen. 6:5; below, Numb. 6:8; 10:9. Esau also hated Jacob, as stated (in Gen. 27:41): AND ESAU SAID IN HIS HEART: <LET THE DAYS OF MOURNING FOR MY FATHER COME, AND I WILL KILL MY BROTHER JACOB>. Moreover, the tribes hated Joseph, as stated (in Gen. 37:4): THEY HATED HIM. So like which brother? Israel said: Like Moses and Aaron, as stated (in Ps. 133:1): SEE HOW GOOD AND HOW PLEASANT IT IS <FOR KINDRED TO DWELL TOGETHER>, since they loved each other and cherished each other. Thus when Moses received the kingship and Aaron < received > the high priesthood, they were not jealous of each other. Rather they were happy in each other's greatness.¹¹²See below, Lev. 3:5. You know yourself it to be so. You find that, when the Holy One said to Moses (in Exod. 3:10): SO COME NOW, I WILL SEND YOU UNTO PHARAOH…, Moses said to him (in Exod. 4:13): PLEASE MAKE < SOMEONE ELSE YOUR AGENT>. Do you imagine that Moses may have delayed in order not to go? He only acted out of respect for Aaron. Moses said: Before I arose, Aaron had been prophesying to them for eighty years. He <is the one> of whom it is stated (in Ezek. 20:5): I MADE MYSELF KNOWN TO THEM IN THE LAND OF EGYPT. And where is it shown that Aaron prophesied to them? Where it is stated (in I Sam. 2:27–28): NOW A MAN OF GOD CAME UNTO ELI AND SAID UNTO HIM: THUS SAYS THE LORD: I SURELY REVEALED MYSELF {TO} [UNTO] YOUR FATHER'S HOUSE IN EGYPT, WHEN THEY BELONGED TO PHARAOH'S HOUSE; AND I CHOSE HIM FROM ALL THE TRIBES OF ISRAEL TO BE MY PRIEST.¹¹³The midrash seems to ignore the fact that what the Holy One says here is introduced by an interrogative particle. He said to him: All these years Aaron has prophesied to them. So am I now to go to them in my brother's domain so that he will be upset? For that reason Moses did not desire to go. The Holy One said to him: Your brother Aaron will not be upset over this matter. Rather he will be happy. You yourself know that he is going out for a meeting¹¹⁴Gk.: apante, apantesis. with you. It is so stated (in Exod. 4:14): SEE, HE IS SETTING OUT TO MEET YOU; AND WHEN HE SEES YOU, HE WILL BE HAPPY IN HIS HEART: not in his mouth alone but in his heart, his heart more than his mouth. WHEN HE SEES YOU, HE WILL BE HAPPY IN HIS HEART. R. Simeon ben Johay said: The heart that was happy at his brother's greatness shall put on Urim and Thummim, as stated (in Exod. 28:30): AND INSIDE THE BREAST PLATE OF JUDGMENT YOU SHALL PUT THE URIM AND THUMMIM SO THAT THEY SHALL BE UPON AARON'S HEART. Ergo (In Exod. 4:14): AND ALSO SEE, HE IS SETTING OUT TO MEET YOU; AND WHEN HE SEES YOU, HE WILL BE HAPPY IN HIS HEART. When <the Holy One> had said this to him, <Moses> took it upon himself to go. Immediately the Holy One revealed himself to Aaron. He said to him: Go out to meet your brother Moses so that he may know that you are happy over the matter. It is therefore stated (in Exod. 4:27): GO INTO THE DESERT TO MEET MOSES. Ergo (in Cant. 8:1): IF ONLY YOU COULD BE TO ME LIKE A BROTHER, like Moses and Aaron who loved each other. (Ibid., cont.:) IF I MET YOU OUTSIDE, I WOULD KISS YOU. (Exod. 4:27:) SO HE WENT TO MEET HIM ON THE MOUNTAIN OF GOD AND KISSED HIM.