Aharon stood as the Kohen Gadol but would forever remain humbled by his crushing failure at the altar of the Golden Calf. A powerful sin indeed. Yet it was precisely because of his remembrance of his dreadful sin that he was most worthy to stand in the service of God. That remembrance inspired the humility that made him great.
Only the truly humble can be made great. And only he who has sinned can know humility. Maharitz teaches that it was because he sinned that Aharon was ordained by God to serve as Kohen Gadol. How would it have been possible for him to personally identify with the humbled sinner’s need for atonement without having personally experienced the humbling need for forgiveness?
“Why are you ashamed of the Golden Calf?” Moshe asked Aharon. Lekach nivecharta. “You were granted the humbling opportunity to sin so that you would then be able to atone for all sinners.”
As Mishlei teaches us, humility raises up while pride only serves to bring down.