(Devarim 33:6) "Reuven shall live and he shall not die": How is this related to what precedes [("together, the tribes of Israel")]? This is analogous to (the situation of) a king, who visits his sons on occasion. When he takes leave of them, they and his kinsmen come to escort him. He says to them: "My sons, is there anything that you need? Is there anything on your mind?" They answer: "Father, there is nothing that we need and nothing that we desire of you but that you forgive our big brother." If not for the tribes' (intercession), the L-rd would not have forgiven Reuven (for the episode of Bilhah [viz. Bereshith 35:22]) — wherefore it is written (at this point) "together, the tribes of Israel."