Personality Types as a Path to Self-Improvement

The majority of parshat Tetzaveh focuses on the garments of the Kohanim. The first pasuk of this section (28:1) starts with Hashem commanding Moshe: "V'atah hakreiv elecha et Aharon achicha - Bring close to you Aharon your brother." The peshat is that Hashem instructs Moshe to separate Aharon and his sons from Bnei Yisroel and bring them close to him to annoint them as the "kohanim."

Is there a deeper message here?