Why not another?
In Vayigash when yosef revealed himself to the brothers its says they could not answer them b/c they were “nivhalu m’panav”. Sfas emes asks whats with the loshan of “mipanuv”? Whats with when yaakov saw yosef rashi says “he was seen by yaakov”?? So the pri tzadok answers with a peladika yisod in this whole story. He quotes a posek from miketz that when the bros met yosef yosef made himself like a stranger “vyaitnaker”. He explains the root comes from “nachri” which is a goy, basicaly yosef hid his kedusha, b/c forsure if your a bnei yaakov youl notice a finer face. When yaakov heard yosef was alive it says he only believed it when he saw the wagons Rashi-the last thing they learnt was egla arufa. Why did he need to see that? he didnt believe the bros?? they were the shivtei ka!! And why did yosef send it he thought his father wouldent believe them?? What was this sign? The egla arufa when the beis din says we didnt kill him, the gemara asks, why would you think they are killers? da teretz is were choshed
they didnt escort him. The gemara learns from there that the kapara will only be a kapara if they are m’lave the person all the way. So if they werent m’lave its not a good kapara whereas they are plain killers. That is why there is malave malka so we can be mamshich the kedusha of shaabos through out the week. Theres a medrash when yaakov saw yosef the last time b4 the bros sold himhe said to yosef i need to tell you over the torah of eglah arufa so when you go on your way you wont part from your kedusha. So when yaakov didnt believe the bros it was about his kedusha. Yosef sent the wagons to show that when yaakov was m’lave him with that torah it stayed with him. So when yaakov saw yosefs face and he saw him like rashi said b4 its b/c he was lookinig for the kedusha in his face.