In the inaugural speech at the Mizrachi Teachers Institute in Jerusalem during Chanukah 1932, Rav Kook said:

People mistake the sacred and the secular for adversaries at war with one another. But in truth, national life cannot exist unless both of these values are fully developed and channeled toward building the nation. Hence, we must endeavor to fuse them and imbue the secular with the holy.

Yet, concurrent with the act of kiddush [sanctification] is havdalah [differentiation], whose purpose is to prevent the blurring of the distinction between the sacred and the secular, to prevent the debasement of the sacred and its misuse for secular purposes. There is a perfect holiness from whose essence and substance we draw, yet we are mandated to guard it from any secular aspects which may dull the richness of the sacred.

Halachah forbids us to fashion a candelabrum similar to the one used in the Temple; that is, the sacred protects itself from any secular invasion which may diminish its worth. Through this very self-protection, the sacred vivifies and fortifies the secular.

The Greek mind asserted that no holiness pervades the world of action. But Knesset Yisrael knows how to join heaven and earth, to unite sacred and profane, to sanctify ourselves with that which is permissible. This complete unification grows out of our maintaining the barriers, our knowledge of how to distinguish between the sacred and the secular. Eternal Israel is built on these complementary principles of unification and distinction.

In an institution in which both the sacred Written and Oral Law are studied along with secular disciplines, we must not forget that our ancient battle against Greek culture has not yet ceased. If we are careless, the sacred will become profane.

We must remember that we are descendants of those heroes who sacrificed their lives to guard the holy. We must be ever watchful that our study of Torah does not degenerate into a study of literature, not even a study of national literature or an ancient science. Torah is the word of the Living God. All pragmatic activities must be illuminated by the light of the sanctity of the Torah and its precepts; "Your word is a lamp for my feet and a light for my path" (Psalms 119:5).

(From 'Celebration of the Soul' by R. Pesach Jaffe, pp. 99-100)