P arshas Acharei Mos–Kedoshim
“He should not come at all times into the Kodesh… so that he shouldn’t die…” (Vayikra 16:2)
Rashi explains that because the Shechinah is revealed there Aharon shouldn’t get accustomed to going there.
Habit is the greatest enemy of holiness. When a person reaches an elevated level and his soul is glowing with sparks of holy fire familiarity puts out the coals one by one until the fire is extinguished.
The Tosefta (Parah perek beis) comments that even Aharon who went into the Kodesh Hakodoshim for seven days in complete holy seclusion was at risk of getting too accustomed to coming and going in the Kodesh.
