Responsa su Levitico 25:36

There is a third type of danger due not to carelessness or to neglect, as are the above types, but to special circumstances involving the relative safety of a man and his fellowman. Thus, the famous case given in the Talmud (Baba Metziah 62a), of the two men in the desert with drinking water enough for only one. Whose life is to be preserved? This is based upon the verse in Leviticus 25:36: "Thy brother shall live with thee," (and is first found in Sifra to this verse), and ends with Akiba's statement: "Your life must come first."