וַֽיְהִ֞י כִּי־בָ֣אנוּ אֶל־הַמָּל֗וֹן וַֽנִּפְתְּחָה֙ אֶת־אַמְתְּחֹתֵ֔ינוּ וְהִנֵּ֤ה כֶֽסֶף־אִישׁ֙ בְּפִ֣י אַמְתַּחְתּ֔וֹ כַּסְפֵּ֖נוּ בְּמִשְׁקָל֑וֹ וַנָּ֥שֶׁב אֹת֖וֹ בְּיָדֵֽנוּ׃
And it came to pass, when we came to the lodging-place, that we opened our sacks, and, behold, every man’s money was in the mouth of his sack, our money in full weight; and we have brought it back in our hand.
Sforno on Genesis
כספנו במשקלו, not only the same amount of money, but the identical coins which we had brought here. This is why we did not think that there had been a mix up with other people’s money.
Rav Hirsch on Torah
ונפתחה, wir öffneten ganz arglos, ohne etwas zu ahnen.