Birthright, the advantages accruing eldest son. These were not definitely fixed in patriarchal times. Great respect was paid to him in the household, and, as the family widened into a tribe, this grew into a sustained authority, undefined save by custom, in all matters of common interest. Thus the “princes” of the congregation had probably rights of primogeniture. Num. 7:2; 21:18; 25:14. Gradually the rights of the eldest son came to be more definite: (1) The functions of the priesthood in the family, with the paternal blessing. (2) A “double portion” of the paternal property was allotted by the Mosaic law. Deut. 21:15-17. (3) The eldest son succeeded to the official authority of the father. The first-born of the king was his successor by law. 2 Chron. 21:3. In all these Jesus was the first-born of the Father.