The question is, if Leviticus is composed of commandments of God, how does Rabbinical authority cahnge it? The Torah gives authority of interpretation.
If there arise a matter too hard for thee in judgment, between blood and blood, between plea and plea, and between stroke and stroke, even matters of controversy within thy gates; then shalt thou arise, and get thee up unto the place which the LORD thy God shall choose.
And thou shall come unto the priests the Levites, and unto the judge that shall be in those days; and thou shalt inquire; and they shall declare unto thee the sentence of judgment.
And thou shalt do according to the tenor of the sentence, which they shall declare unto thee from that place which the LORD shall choose; and thou shalt observe to do according to all that they shall teach thee.
According to the law which they shall teach thee, and according to the judgment which they shall tell thee, thou shalt do; thou shalt not turn aside from the sentence which they shall declare unto thee, to the right hand, nor to the left. (Deuteronomy 17:8-11)
Matrilineal descent? Is that custom a mandate from God or men?
Isaac was Abraham's heir; Ishmael was not. You should be able to figure it out from there. There are other scriptural examples too, but this should suffice.
Who wrote Deuteronomy?
Isaac was Abraham's heir; Ishmael was not.
I can how this can be interpreted as matrilineal descent. But it can also be interpreted as God's plans for those two individuals, regardless of whose womb they cam from, or that they cam from a womb at all. Is there any other more overt Biblical passage or commandment from God or one His prophets that would indicate descent through female line?
I think it much more likely that the custom devolves from the fact that the mother is the primary conditioner of Jewish principles and conditioning from the earliest of ages. From the many Jews I've known and those of whom I've known their background, that makes the most practical sense.
I would tend to doubt that the custom is commanded by God.
