וַיֹּ֨אמֶר יוֹסֵ֧ף אֶל־אֶחָ֛יו גְּשׁוּ־נָ֥א אֵלַ֖י וַיִּגָּ֑שׁוּ וַיֹּ֗אמֶר אֲנִי֙ יוֹסֵ֣ף אֲחִיכֶ֔ם אֲשֶׁר־מְכַרְתֶּ֥ם אֹתִ֖י מִצְרָֽיְמָה׃
約瑟對他兄弟們說：«請你們靠近我。» 他們就靠近了。他說：«我就是你們的兄弟約瑟，就是你們賣到埃及去的那個人。»
Rashi
גשו נא אלי STEP NEAR TO ME, I PRAY YOU — He saw that they recoiled and he said to himself “Now my brothers feel ashamed”. He therefore called to them and showed them that he was circumcised. (Genesis Rabbah 93:10).
Radak
גשו נא אלי, seeing his brothers in a state of shock, Joseph called to them and encouraged them to come closer and to stop being afraid of him. According to Bereshit Rabbah 93,8 he showed them that he was circumcised in order that they should believe him when he claimed to be their brother. Everything else he told them is quite clear and does not require further explanation.
Sforno
גשו נא אלי, so that not all the people hearing me cry can see that it is I who is crying.