Vort on Parshas Mikaitz
ויכר יוסף את אחיו והם לא הכירוהו וגו’ (מקץ מב: ח)
And Yosef recognized his brothers, and they didn’t recognize him.
Rashi comments that Yosef looked identical to Yaakov, so why didn’t his brothers remember him? Yosef looked his age at 39 years, just like his father looked at 39 years. Therefore his brothers couldn’t recognize him since Yaakov started having children when he was more than eighty years old, and they never saw their father at that age.