166. This is what Rabbi Shimon said, It is written, "But on the first day you shall remove leaven out of your houses; for whoever eats leavened bread" (Shemot 12:15). I have explained it thus, leaven and leavened dough are one level, and are all the same. The other dominion is the ministers appointed over the other nations, whom we call Evil Inclination, another dominion, strange El, Other Elohim. Here also, leaven, leavened dough and leavened bread are all the same. The Holy One, blessed be He, said, 'All these years, you were under the authority of others and served another nation. From now on, you are free men. "But on the first day you shall remove leaven out of your houses...you shall eat nothing leavened" (Ibid. 20) and "there shall no leavened bread be seen with you" (Shemot 13:7).
167. Rabbi Yehuda said, If so, WE SHOULD NOT EAT LEAVEN all the days of the year. Why only seven days, as it is written, "Seven days shall there be no leaven found in your houses," and not more? He said to him, At all times that a person is obliged to show himself free, it is required NOT TO EAT LEAVENED BREAD, but whenever he is not obligated then he does not need TO OBSERVE THE PROHIBITION OF LEAVENED BREAD.
168. This is comparable to a king who appointed a person to be a minister. He rejoiced and wore clothes of glory all those days that he was being elevated to this level, but afterwards he did not need it. The following year, he observed those days that he rose to this honor and wore those clothes, and he did so each and every year. Similarly with Yisrael, it is written, "Seven days shall there be no leaven found," for they are days of rejoicing, the days that they arose to this honor, and went out of another bondage. Every year, they observed those days when they rose to this honor and went out of another authority and came under holy authority. Therefore, it is written, "Seven days shall you eat unleavened bread."