ויאמר משה אל אהרן קרב אל המזבח…(שמיני ט:ז)

Rashi says: “שהיה אהרן בוש וירא לגשת אמר לו משה למה אתה בוש לכך נבחרתי” –“Aharon was embarrassed and hesitant to approach. Moshe said to him: ‘Why are you embarrassed? It is for this that you were chosen.’”

Moshe explained to Aharon that shamefulness is a good trait, but it shouldn’t keep you back from performing a mitzvah.  Just the opposite.  With this trait, you shall serve Hashem and fulfill His commandments.