Rabbi Mayer Twersky
You Shall Be Holy (1)
Speak to the entire assembly of the children of Israel and say to them: You shall be holy, for holy am I, Hashem your God (Vayikra 19:2)
The mandate of kedoshim tiheyu is the lodestar of Jewish existence. (2) What, however, does a life of kedusha entail? Let us approach this question etymologically. Kedusha etymologically denotes separateness. (3) Hence, Hakadosh baruch hu who is transcendent and infinite is described as kadosh. He is entirely separate - above and beyond human categories of thought and conception. (4) "Holy, holy, holy is Hashem, Master of Legions, the whole world is filled with His glory." (5)
Since kedusha denotes separateness, when predicated of man, it denotes abstinence. Hence, the Sifrei's explanation of "you shall be holy" to mean "you shall abstain" (perushim tiheyu). According to Rashi, (6) the Sifrei intends abstinence from sexual immorality. Accroding to Ramban, (7) the Sifrei intends a broader mandate of abstinence - viz; to refrain from all materialistic excess and hedonistic practices. But clearly kedusha denotes separateness.
Kedusha etymologically also denotes consecration, designation. (8) One is makdish an animal as a korban; kedusha in this context is synonymous with consecration. In fact, the sanctity of the animal owes to its consecration.
Now clearly the concepts of separateness and consecration are interrelated, and, in reality, kedusha has but one etymology. Consecration pre-supposes separateness. Accordingly, the act of consecrating an animal imposes a prohibition against benefiting from or using the animal for any purpose other than sacrifice. The Torah in describing the Nazarite beautifully encapsulates the spiritual symbiosis of separateness and consecration. "All the days of his abstinence he is holy to Hashem".(9)
To repeat our original question: what does a life of kedusha entail? A focused, consecrated life. (10) But focus and consecration perforce assume separateness. Separating oneself from pursuit of pleasure, separateness from careerism, and the like. In a word, separating oneself from the mundane as an end unto itself and all forms of egotism. Such separateness facilitates and fosters consecration. Consecrating oneself - one's ambitions, energies, talents, and above all, time - to Hashem Yisborach.
Only a select few have - or should - become Nazirites. Nevertheless the mandate of kedoshim tiheyu (albeit without the added mitzvos of the Nazarite) is directed to all Jews. "Speak to the entire assembly of the children of Israel and say to them: you shall be holy...." We must strive to cultivate this single-minded focus in all realms of life - both the seemingly mundane as well as the overtly spiritual. By way of example, when we pursue a pampered, indulgent life style, we have lost the focus of kedoshim tiheyu. When we come to shul but engage in idle talk during davening, we have lost the focus of kedoshim tiheyu. And so forth.
Kedoshim tiheyu is a demanding, yet enthralling and encouraging mandate. Its demands notwithstanding, the Torah assures us that everyone of us is capable of achieving kedusha "for holy am I, Hashem your God".