וַיֹּ֨אמֶר יוֹסֵ֤ף אֶל־אֶחָיו֙ אֲנִ֣י יוֹסֵ֔ף הַע֥וֹד אָבִ֖י חָ֑י וְלֹֽא־יָכְל֤וּ אֶחָיו֙ לַעֲנ֣וֹת אֹת֔וֹ כִּ֥י נִבְהֲל֖וּ מִפָּנָֽיו׃
요셉이 그 형들에게 이르되 나는 요셉이라 내 아버지께서 아직 살아 계시니이까 형들이 그 앞에서 놀라서 능히 대답하지 못하는지라
Chizkuni
כי נבהלו מפניו, “for they were frightened of him.” They were afraid of what he might do to them as reprisals for what they had done to him.
Da'at Zekenim
ולא יכלו אחיו לענות אותו, “and his brothers were unable to answer him;” Rabbi Joseph Kara, explains this line as follows: the brothers on the one hand believed him when he said that his name was Joseph; however they could not believe that he was the Joseph whom they had sold into slavery, and that in the interval he had risen to such an exalted position, ruler over mighty Egypt. (Compare how Joseph is described in Psalms 105,17-18)