Genesis 49:1-4 KJV

1 And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you that which shall befall you in the last days.

2 Gather yourselves together, and hear, ye sons of Jacob; and hearken unto Israel your father.

3 Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:

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.