Bereshis 49:2-4

Orthodox Jewish Bible

² Gather yourselves together, and hear, ye Bnei Ya’akov; and pay heed unto Yisroel Avichem.

³ Reuven, thou art my bechor, my koach, and the reshit of my strength, the excellency of honor, and excellency of oz (power):

⁴ Unstable as mayim, thou shalt not excel; because thou wentest up to mishkevei avicha (thy father’s bed, i.e. incest); then defiledst thou it; he went up to my couch.