ואל בני ישראל תדבר לאמר קחו שעיר עזים לחטאת ועגל וכבש ... לעולה
The Sifra identifies the sins for which the eigal, calf, and the se’ir izzim, he-goat, atoned. The eigal was offered to expiate the sin of the golden calf. The goat served as an atonement for the sin of selling Yosef as a slave and slaughtering a goat in order to dip Yosef’s multi-colored tunic into its blood. Understandably, the sin of the Golden Calf was the catalyst for the Mishkan which atoned for it. What does mechiras Yosef, the sale of Yosef, have to do with the eighth day of milluim, inauguration, of the Mishkan? Some form of identification was…