3 "Reuben, you are my firstborn, my might, the first sign of my strength, excelling in honor, excelling in power.
17 He must acknowledge the son of his unloved wife as the firstborn by giving him a double share of all he has. That son is the first sign of his father's strength. The right of the firstborn belongs to him.
(Read Deuteronomy 21:15-17)
This law restrains men from disinheriting their eldest sons without just cause. The principle in this case as to children, is still binding to parents; they must give children their right without partiality.
Matthew Henry's Commentary on Genesis 49:3
Commentary on Genesis 49:3-7
(Read Genesis 49:3-7)
Reuben was the first-born; but by gross sin, he forfeited the birthright. The character of Reuben is, that he was unstable as water. Men do not thrive, because they do not fix. Reuben's sin left a lasting infamy upon his family. Let us never do evil, then we need not fear being told of it. Simeon and Levi were passionate and revengeful. The murder of the Shechemites is a proof of this. Jacob protested against that barbarous act. Our soul is our honour; by its powers we are distinguished from, and raised above, the beasts that perish. We ought, from our hearts, to abhor all bloody and mischievous men. Cursed be their anger. Jacob does not curse their persons, but their lusts. I will divide them. The sentence as it respects Levi was turned into a blessing. This tribe performed an acceptable service in their zeal against the worshippers of the golden calf, Exodus 32. Being set apart to God as priests, they were in that character scattered through the nation of Israel.