מדרש על בבא בתרא 143:11

Our rabbis taught: Brothers who are partners and who increased assets, even if their father left them only a bed or an axe, divide equally. Why? Because they are brothers (Baba Bathra 143b), and you find that partners who are brothers were beloved before the Holy One, blessed be He, like Moses and Aaron, about whom the community of Israel said before the Holy One, blessed be He: "Who will make you like a brother to me etc." Since the Holy One, blessed be He, calls Israel "brothers", as it says "For my brothers and companions' sake etc." (Psalms 122:8), she said before Him: "Who will make you like a brother to me", not like all brothers who hated one another, but like Moses and Aaron who loved one another and raised one another and rejoiced in each other’s greatness (Numbers Rabbah 21:3, Exodus Rabbah 5:5, Tanhuma Shemot 27). Know this from what we read regarding "And these are the generations of Aaron and etc."