Yesod brings with it the concept of “connection.” This is why it is the Sefirah associated with Joseph in the Torah.
Joseph was the lynch pin to bring down the G-dly wisdom and understanding he had processed (through the respective descending Sefirot of Netzach and Hod – called ‘the wings of Yesod’), down to his brothers.
Five of the greatest words of connection in the Torah were: “Ani Yosef, Ha-Od Avi Chai? … I am Joseph, does my father still live?”