Contradiction with Genesis 49:4
Being labeled as unstable as water contradicts the dignity and power mentioned in Genesis 49:3.
Genesis 49:4: Unstable as water, thou shalt not excel; because thou wentest up to thy father's bed; then defiledst thou [it]: he went up to my couch. [thou shalt...: Heb. do not thou excel] [he went...: or, my couch is gone]
Contradiction with 1 Chronicles 5:1
This verse contradicts Genesis 49:3 by stating that Reuben's birthright was given to the sons of Joseph due to Reuben's transgression.
1 Chronicles 5:1: Now the sons of Reuben the firstborn of Israel, (for he [was] the firstborn; but, forasmuch as he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.
Paradox #1
Genesis 49:3 presents Reuben as the firstborn and with preeminence, yet other parts of the Bible depict Reuben losing his birthright due to his actions. This creates a contradiction between his described status and the eventual outcome of his lineage.
Paradox #2
Genesis 49:3 describes Reuben as the firstborn son of Jacob, and it emphasizes his strength and dignity. However, a contradiction arises because, despite being the firstborn, Reuben does not receive the principal blessing or leadership role in Jacob's lineage. This is because Reuben later acts dishonorably by sleeping with his father's concubine, which leads Jacob to eventually give the primary blessing to Judah and Joseph's sons. This causes a conflict between Reuben's initial status as firstborn and what he actually receives in terms of inheritance and legacy.