NOTES for Gen 44:1-34
There is today, and there was in antiquity, a certain understanding, not always clear but common to all peoples: like is redeemed by like. If you killed a person, be ready to die. If you stole, be ready to return what was stolen many times over. And now: how could the sale of one's own brother into slavery be redeemed? In a very obvious way: by freeing one's brother from slavery and becoming a slave in his place. Something like this happens after the staged "theft" of Joseph's cup by his brothers, arranged on Joseph's orders.
It is completely clear that this staged scene is part of the work Joseph is doing with his brothers. He has to let them feel what it is like to be guilty without guilt, and in such a way that it is absolutely impossible to justify yourself, even if you are right a thousand times over. Perhaps this will make it clearer to them what Joseph felt when his brothers sold him to the merchants of a passing caravan. Feeling it is important, but it is not enough. What is at issue is spiritual work. Joseph needs to understand what choice the brothers will make when they have to decide what to do now that their youngest brother is to remain in Egypt in slavery. The situation mirrors his own: he too faced slavery in Egypt without any guilt.
One could say that the brothers were still fortunate: for the "theft," the youngest of them faced the death penalty, and only by Joseph's mercy did he remain alive, though in slavery. So it had once been with Joseph himself: for him too slavery in Egypt became mercy, a substitute for death, which had seemed almost inevitable. And it is here that Judah offered himself as a slave in Benjamin's place.
This offer settles the matter: only a little while remains, and Joseph will reveal himself to his brothers; the test is over. Why precisely now? It is not hard to understand: among the brothers there was at least one who was ready to redeem what had been done to Joseph. To redeem it, of course, still in the most familiar, traditional sense, but even here there is already what is present in every redemption and without which no redemption is possible by definition: the readiness to take upon oneself the consequences of another person's actions and another person's sins. To take them on only out of love, without any compulsion. Now the sin against Joseph had been redeemed, and Joseph could reveal himself to his brothers.