It is extraordinary how many people come into my office believing the oldest son somehow has some inherent right to govern the estate of the parents.
Being a lawyer, I start looking for authority for this rule. I start with Exodus 13-
The Lord said to Moses, “Set apart for me the first boy born in every family. The oldest son of every Israelite mother belongs to me. Every male animal that is born first to its mother also belongs to me.”
And thus Primogeniture was born, as well as animal law.
Note the ancient practice of Primogeniture called for the first born male to actually inherit, not just govern his parents estate. This lead to the ancient practice of fratricide as well.
Cain said to his brother Abel, “Let’s go out to the field.”
And while they were in the field, Cain attacked his brother Abel and killed him.
It has never been clear to me his motive, Abel was not the oldest. Cain was going to inherit anyway. Perhaps Cain got bad legal advise from the internet.
Here is something to keep the modern mind away from such sin; slayers do not inherit. See Revised Code of Washington.