First-born Rights (the Right of Primogeniture)

The eldest son was given a double share of the inheritance — this is called the birthright or the right of primogeniture.

The eldest son had special rights and responsibilities in relation to his family. He was given a double share of the inheritance, as we read, among other places, in Genesis 25:30-33.
He was also the first person responsible for family affairs, such as for the material care of the family or the taking of revenge (see blood vengeance).

For animals, too, the eldest offspring was special. The first offspring of cattle, sheep and goats were set aside for God. They could stay with the mother for seven days, but on the eighth day they were sacrificed. According to Exodus 13:11-16 this also applied to the eldest sons. But for them, a sum of money was paid to the priest. This dedication of the first-born to God was a reminder of the liberation from Egypt. At that time, God killed the first-borns of both man and beast in Egypt.

The people of Israel are sometimes called the first-born of God. This also indicates the special status of the people.
Jesus too is called the first-born several times in the New Testament. He is the first-born of all his brothers and sisters (Romans 8:29) and of the creation (Colossians 1:15).