Yom Kippur is the holiest day of the year. On this day, we do not drink, eat, bathe, or wear leather shoes. It's not difficult to feel holy on this day, when so many things are different. However, the section of the Torah that explains the laws of Yom Kippur is called Acharei.
This teaches us that the life of a Jew should not be holy only on Yom Kippur, but that through the observance of mitzvot (precepts), we ensure that, even "after" Yom Kippur, our life continues to be holy.
Extracted from Please tell me what the Rebbe says.