Let us look closely at what sign those two and a half tribes hold who receive the land of inheritance through Moses, and what sign the remainder of the nine and a half tribes hold who receive the promise of the holy land through Jesus [Joshua].First of all, I think it is impossible for it to have happened accidentally that those who receive a portion through Moses were all firstborn. For Reuben was the firstborn of Leah; Gad, the firstborn of Zilpah;4 and Manasseh, the firstborn of Asenath the Egyptian whom Joseph married, the daughter of Potiphar the priest of Heliopolis. For myself, I can never be persuaded that it was by chance that the firstborn were the only ones whose inheritance was determined through Moses. Rather, I believe that in these things the design of two groups of people was already foreshadowed at that time: One would seem to be the firstborn according to the order of nature; the other, the people who would receive the blessing of their inheritance through faith and grace.
Rest is not given first to those who through Moses receive the inheritance—that is, those who pleased God through the law—unless they assist their brothers in the battles. Only women and infants receive rest through Moses. The others do not rest but go out to the aid of their brothers.…Thus those who are strong men, their loins armed and girded with truth, go forth to our aid and fight with us. But “infants and women” do not go out to our battle. This is not an astonishing thing, for an infant is said to be one who does not speak. How is a person able to assist me who has spoken nothing, the one of whom I discover nothing that I may read, the one who does not instruct me by a word? But the apostle says that a woman is a “weak vessel.” Suitably, therefore, a weak vessel does not come to the conflict lest it be broken in pieces and destroyed. For concerning our Lord Jesus, it is also said in the Gospels that “he did not break a bruised reed.”
[AD 253] Origen of Alexandria on Joshua 1:12-15