What is holiness? The Ramban (Rabbi Moshe ben Nachman of Barcelona, Spain) says it means "removed from the mundane."

In this week's Parsha Emor, we learn about the innate holiness found within the Kohen, which translates into a different level of responsibility they have towards the collective. 

In truth, all of us are called Kohanim. As the Torah says, "I will make you a nation of Kohanim and holy assembly." 

This means that holiness is found inside of us, as the verse says, "say (Emor) to the Kohanim In; the famous commentator of the Torah, Rashi (Rabbi Shlomo Yitzchaki, Trois France), says that this means that the older Kohanim have an obligation of "illuminating" the younger ones.