the animal sacrifices were inadequate to redeem, but merely sufficed as reminders of debt and acknowledgement of same. "Even a brother cannot redeem a brother." Yet each human being/brother is priceless and beyond any human's ability to redeem, though a brother were to give his life, and everything he owned. [Even if he were a Rothschild.]

Through circumstances partly beyond his control, said bro. will have inherited and accumulated sin [shortcomings, imperfections], so that he will no longer satisfy God's perfect justice as a ransom. God created Adam and Eve perfect and they had the potential to produce another generation of perfect offspring, and so forth, but the opposite happened to result, through their free will [ Adam's, at least]. Who then is able to provide a ransom? And who is able to demand one? Not Satan, who was not the giver in 1st place, and who only rules by God's permission.
Satan made an accusation [he told Eve that God was a liar, and said humans were a faulty creation [ Book of Job] who would only serve God if he coddled them.] And, for the benefit of all observers, both in heaven and on earth, God has allowed time for Satan to prove these accusations, or not, in such thoroughness that these accusations can and need never again be raised.
I think brother-in-law marriage, [Levirite marriage], and many more principles come into it and I hope we can still discuss tomorrow.