וַיִּשָּׂ֣א עֵינָ֗יו וַיַּ֞רְא אֶת־בִּנְיָמִ֣ין אָחִיו֮ בֶּן־אִמּוֹ֒ וַיֹּ֗אמֶר הֲזֶה֙ אֲחִיכֶ֣ם הַקָּטֹ֔ן אֲשֶׁ֥ר אֲמַרְתֶּ֖ם אֵלָ֑י וַיֹּאמַ֕ר אֱלֹהִ֥ים יָחְנְךָ֖ בְּנִֽי׃
And he lifted up his eyes, and saw Benjamin his brother, his mother’s son, and said: ‘Is this your youngest brother of whom ye spoke unto me?’ And he said: ‘God be gracious unto thee, my son.’
Rashi on Genesis
אלהים יחנך בני GOD BE GRACIOUS UNTO THEE, MY SON — With regard of the other sons of Jacob we have heard the expression “grace” used — viz., (33:5) “[The children] whom God hath graciously given (חנן) to thy servant”. But Benjamin had not then been born and therefore was not included amongst the children of whom Jacob used this term; on this account Joseph used the term “grace” in blessing him (Genesis Rabbah 92:5).
Sforno on Genesis
Elokim be gracious. Since you are the only remaining son of your mother, as the brother’s had told him (see 44:20), may Hashem give you grace so that your brothers will feel affection towards you.
Radak on Genesis
וישא עיניו, seeing that they all surrounded him without any specific order of seniority, Joseph looked up in order to recognise his brother Binyamin, [who had only been about 10 years old at the time he had last seen him. Ed.]