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Before we attempt to answer the question, we must understand that there are two aspects to attaining true freedom. First, one needs to be physically independent of all foreign subjugation. Complete freedom, however, also requires freedom of the spirit, for the soul is not free if it is subjected to external demands that prevent it from following the path of its inner truth.
Indeed, the difference between a slave and a free person is not just a matter of social standing. One may find an educated slave whose spirit is free, and a free person with the mindset of a slave. So, what makes us truly free? When we are able to be faithful to our inner self, to the truth of our divine image [tzelem elokim] – then we can live a fulfilled life, a life focused on our soul’s inner goals. One whose spirit is servile, conversely, will never experience this sense of true self-fulfillment; his happiness will always depend upon the approval of others who dominate him.
What, then, is chametz? It is a foreign substance added to the dough; it makes the dough rise and changes the dough’s natural shape and characteristics. Destruction of all leaven in the house, therefore, symbolizes the removal of all foreign influences and constraints that prevent us from realizing our spiritual aspirations.
These two levels of independence, physical and spiritual, exist on both the individual and the national level. An independent people must be free not only from external rule, but also from foreign domination in the cultural and spiritual spheres.
For the Israelites in Egypt, it was precisely at the hour of imminent redemption that the dangers of these foreign “leavening” forces were the greatest. At the time of great upheaval, true permanent emancipation was not a given. Would the Israelites succeed in freeing themselves, not only from Egyptian bondage, but also from the idolatrous culture in which they had lived for hundreds of years? To commemorate their complete liberation from Egypt, both physical and spiritual, the Passover holiday of freedom requires the removal of all foreign leavening agents.
Freedom is the fulfillment of our inner essence. We need to aspire to the lofty freedom of those who left Egypt. To the Israelites of that generation, God revealed himself, and brought them into His service. This is truly the highest form of freedom, as the sages taught in Avot (6:2): "The Tablets were God’s handiwork, and the script was the script of God, engraved on the Tablets (Shemos 32:16); do not read chorus (engraved), rather chairus (free), only one who studies Torah is free because anyone who studies Torah becomes elevated."
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As I mentioned, I found this d'var Torah very interesting and perhaps in need of some clarification. I, of course, am in no way pretending to be a spokesman for Rav Kook or claim to be privy to some special information. Rather, I am simply presenting my understanding of this d'var Torah, and please feel free to disagree with me if you feel so inclined.
The premise of this d'var Torah is that chametz is a foreign substance added to the dough. In truth, I do not understand this premise, for although it is true, its relevance escapes me. Meaning, yes, the leavening agent is added to dough to help it rise. However, normal dough - meaning dough without the leavening agent - also rises, and is, of course, subject to the prohibition of chametz if baked for too long. Therefore, the representation of purging chametz as the removal of all foreign influences that prevent us from realizing our spiritual aspirations seems flawed. So, I therefore am at a loss; if anyone could enlighten me I’d be most appreciative.
Ignoring that little snag for a second, let’s move on to my second and most important point. Rav Kook asserts that chametz is a foreign substance added to the dough and that the purging of it symbolizes the removal of all foreign influences and constraints that prevent us from realizing our spiritual aspirations. I think it’s very important to understand that not all foreign influences are bad. Rather, only the foreign influences that prevent us from realizing our spiritual aspirations need to be worried about. In other words, I do not believe that Rav Kook is labeling anything secular as bad. Rather, I feel that he is calling on us to ensure that we are not being influenced by negative influences, specifically the ones that constrain us. These influences and constraints are, of course, subjective.
Third, Rav Kook’s assertion that one may find an educated slave whose spirit is free, and a free person with the mindset of a slave is absolutely true. And this, of course, calls into mind the famous words of Richard Lovelace, a 17th century cavalier poet, written in prison: “Stone walls do not a prison make, Nor iron bars a cage;…If I have freedom in my love, And in my soul am free, Angels alone that soar above Enjoy such liberty.”
Lastly, for a good article on the quote from Avot 6:2, see here.