Aliya Summary: This Aliya prescribes the procedure for consecrating Aaron and his sons as priests. Aaron and his sons were brought to the door of the sanctuary, they immersed in a mikvah (ritual pool), and were dressed in the priestly garments. Moshe then offered various inaugural sacrifices on their behalf.
The very first offering in the Mikdash was symbolic of the Golden Calf and came as an atonement for that sin. It’s interesting to note that while the Golden Calf experience was hurtful towards G-d, it is something not shied away from, but rather confronted. As psychologists would attest, talking about hurtful events help you get over it, and more importantly, forgive those that caused it.