No offering which you shall bring to G‑d shall be made with leaven... shall be offered up before G‑d... (2:17).

Why is leaven so utterly rejected? Because it inflates itself…

- Rabbi Menachem M. Schneerson, the Lubavitcher Rebbe, of righteous memory

G‑d says of the conceited one: "I and he cannot dwell in the same world."

- Talmud, Erchin 15b

On Passover of 1865, Rabbi Sholom DovBer of Lubavitch, then a child of four, was present at the seder of his grandfather, Rabbi Menachem Mendel. An incident that occurred that night stuck in the child's mind.

At the beginning of the seder there is a procedure called yachatz ("divide") in which the middle of the three seder matzohs is broken in two. The greater half is set aside for the afikoman1, and the smaller half remains on the seder plate and is eaten following the reciting of the haggadah.

One of the participants at Rabbi Menachem Mendel's seder was comparing his two matzoh-halves, trying to figure out which was the larger piece. Remarked Rabbi Menachem Mendel: "A 'great one' who needs to be measured, is smaller than the 'small one' he is measuring himself against…"

"From that moment on," related Rabbi Sholom DovBer, "I developed a feeling of contempt toward this sort of 'greatness.'"