Or HaChaim on Genesis 44:16/אור החיים על בראשית מ״ד:ט״ז

1 מה נאמר מה נדבר, "What can we say, how can we speak?" The expression אמירה refers to mild talk, whereas the expression דבור refers to aggressive, tough talk. When the brothers added: מה נצתדק, "how can we justify ourselves?," they referred to their defence in a court of law. They considered that all these trumped up charges were retribution by G'd. The time apparently had come to pay for their guilt. Inasmuch as they were all guilty vis-a-vis G'd, they offered themselves as slaves.

2It is also possible that when the brothers spoke of "how can we justify ourselves?," they referred to the disastrous discovery of the goblet in Benjamin's pouch. This fact had destroyed their collective defence that they had already proven their honesty by having returned the money they had found in their bags upon their return to Canaan; alas, Benjamin had not been with them at the time.

3גם אנחנו, both we, etc. The word גם may be understood as הגם, i.e. "even though the goblet has not been found in our pouches." Inasmuch as the sin the brothers had been guilty of did not include Benjamin at all, seeing he had been far too young to participate in the sale of Joseph, they said: "as well as the one in whose pouch the goblet has been found;" they attributed Benjamin's having been found with the goblet in his pouch as a misfortune that had befallen Benjamin only because he had travelled with sinners such as they. We find a similar use of two apparently not only unrelated but completely contradictory phenomena when the Talmud in Sanhedrin 93 compares "two dried out trees and one moist one," saying that when the dry trees go up in flames even the green tree is burnt up together with them.

4Alternatively, the brothers shifted gears by no longer speaking about the person in whose pouch the goblet was found as being guilty of death, but גם אנחנו "we too" i.e. Benjamin was to be subject to the same penalty they had declared themselves as guilty of in verse 9, namely slavery. They justified this by citing the fact that there were no witnesses to the actual theft. Benjamin was able to plead that he did not know who placed the goblet in his pouch.