en_tn/gen/49/04.md

Uncontrollable as rushing water

Jacob compares Reuben to water in a strong current to emphasize that he cannot control his anger and he is not stable. (See: rc://en/ta/man/jit/figs-simile)

you will not have the preeminence

"you shall not be first among your brothers"

because you went up to your father's bed. Then you defiled it; you went up to my couch

Here "bed" and "couch" stand for Jacob's concubine, Bilhah. Jacob is referring to when Reuben slept with Bilhah (Genesis 35:22). Alternate translation: "because you went to my bed and slept with Bilhah my concubine. You have shamed me" (See: rc://en/ta/man/jit/figs-metonymy)

you went up to your father's bed ... you went up to my couch

Both statements mean the same thing. (See: rc://en/ta/man/jit/figs-parallelism)