Musar sur La Genèse 42:22

Reuben had already hinted at this development when he told his brothers (42,22) that Joseph's blood was being demanded from them. True, they did not at the time understand the deeper meaning of what was happening and what was being said, but the words were inspired by G–d even though He had not revealed their full meaning to the brothers. The mystical dimension of Joseph's historical mission was that he acted in the capacity of forerunner – not only in the story related in our פרשה – but also in the distant future when he will be killed performing a similar mission and his blood will be avenged. This is what he told his brothers when he said: "Now not you have sent me here but G–d, who has placed me in the position of father to Pharaoh."