Only Yosef (tzaddik yesod olam) is impervious to ayin hara (Esav’s eye of doom).
Rochel (malchus) is most vulnerable to ayin hara.
She was also pregnant with Binyomin (an additional malchus element).

Someone must protect Rochel, and Yosef is the only one who can do it.

Shavua Tov!