דַּבְּרוּ אֶל כָּל עֲדַת יִשְׂרָאֵל לֵאמֹר בֶּעָשׂר לַחֹדֶשׁ הַזֶּה וְיִקְחוּ לָהֶם אִישׁ שֶׂה לְבֵית אָבֹת שֶׂה לַבָּיִת
Looking at asor עָשׂר the word for 10th made me think of how the same letters with a change in vowels can be read ashir and that transposing the letters seir, a goat. The associations I considered were the following.
We call matzah lechem oni [poor man's bread]. The flat, plain form of bread presents a contrast to the rich bread that rises with a leavening agent. It becomes lechem ashir as a result of the addition of seor. It's a small thing, but it makes all the difference. The seor (same sound for the letters but with an aleph instead of an ayin) is identified with the yetzer hara, as Chazal say, that we want to do what's right, but the seor in the dough prevents us.
The other representation of the yetzer hara is the seir, as illustrated concretely in the Yom Kippur service that includes a seir leazael. Just as we represent ridding ourselves of what keeps us from inclining to good then, we do so on Pesach by banning all seor and its resulting chametz.
Another word in the verse cited above, לַבָּיִת, made me think of a Purim theme, but I'm not going to wait 11 months to write it down. So bear with me. Mrs. Horowitz cited the Rav as saying that what בָּיִת [household] represents in this context is community. I then thought of the famous Midrash cited by Rashi on Megillas Esther. The text says that Mordechai took Esther lebas [for a daughter]. The Midrash reads it as lebayis to hint at his having married her. However, on the basis of what the Rav said about the house standing for community there could be a more profound significance to the reading of lebayis, that of making Esther see herself as part of the larger Jewish community. Certainly, that is what Mordechai tells her later on when he warns her that there is no self-preservation possible when the Jews are threatened -- only salvation for the whole community.
Related post: http://kallahmagazine.blogspot.com/2016/03/purim-countering-confusion-of.html