The Firstborn Priesthood before the Law of Moses

Before God gave the Law to Moses at Mount Sinai, the father of the family exercised the office of priest. The father handed on his priesthood to his firstborn son by way of a blessing. Saint Thomas Aquinas regards this “primogeniture priesthood” of the firstborn sons as an institution established in natural law. Thomas wrote that natural law guided men to understand this “fatherly” notion of priesthood. The father of the family received a natural charge to teach his family and provide atonement for the sins of his wife and children. The firstborn son naturally became the primary heir and religious head of the extended family. He took his father’s place as the mediator and judge for his family’s religious and legal customs. We see several examples of this paternal priesthood in the book of Genesis. Noah offered blood sacrifices (Gen 8:20) on behalf of his family. Likewise, Abraham and Jacob offered blood sacrifices (Gen 15:9; 22:1-13; 31:54). Isaac offered his own body in sacrifice (Gen 22).

The story about Jacob outwitting his brother for their father’s dying blessing is a story of how Jacob received the covenantal blessings and paternal “ordination” from his father Isaac (cf. Gen 27). The most striking example of paternal priesthood is found in the narrative about Job: Job would send and sanctify them [his family], and he would rise early in the morning and offer burnt offerings according to the number of them all; for Job said, “It may be that my sons have sinned, and cursed God in their hearts.” Thus, Job did continually (Job 1:5).

Job’s fatherhood is intimately bound to his priesthood. The father bore the spiritual authority of his family. The Catholic custom of calling priests “Father,” then, derives from this ancient and natural association between priestly mediation and natural fatherhood.

Excerpt from Taylor Marshall, The Crucified Rabbi: Judaism and the Origins of Catholic Christianity, 2009