What was the sin of Reuben?

Genesis 49 vs. 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. 

 1 Chronicles 5 vs. 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.

1. Reuben was the first born of Jacob.
2. Jacob cursed Reuben that he will never be successful.
3. What sin could a first born commit that will cause his father to curse him?
4. The sin of Reuben is that he slept with his father’s concubine.
5. Parents have a responsibility to train up their children in the way of God, so that they will not become vagabond children.
6. Reuben was at fault for sleeping with his father’s concubine, but Jacob was also at fault for not training up his child in godliness.