While the firstborn Mitzri'im were all dying, the Yidden were secure and protected in their homes, enjoying their Korban Pesach with Matza and Maror. וְאַתֶם לֹא תֵצְאוּ אִיש מִפֶּתַח בֵיתו עַד בֹקֶר יב כב We were protected in our house. This is the night that we became Bnei Yisroel. This symbolizes that being a Yid means being on guard, and being protected by Hashem. When a person speaks Lashon Hara, he isn’t Shomer (on guard of) his mouth, then his 3 forms of Shemira (guards) develop Tzora'as; i.e., his skin, his clothing, and his house. Similarly, in order to be protected on the night of Pesach, all we had to do was to be in a normal, healthy home, and enjoy the Korban Pesach in a happy normal way, since a Yid has a normal house. This is what protected him from the: מַשְחִית destroying angel.
By the Mitzri'im, it says: כֻּלָנוּ מֵתִים יב לג they were ALL dying because one Mitzri house could have all Bechorim (firstborn) from different fathers. This is not a real house (i.e., protection). Yaakov Avinu called Har HaMoria a Bayis (house), and we go like him. (Gemara). On Yom Kippur there were two goats. One went to “Azazel”, an open: שָדֶה field, and one went to Hashem, i.e., in the “Bais” Hamikdash. Yaakov was a: ישֵב אֹהָלִים dweller of tents, and Sara was: הִנֵה בָאֹהֶל concealed in the tent.
A house means stability, with Torah and Tz'niyus, respect, rules, and true Simcha and normalcy; not a wild crazy world without rules. Makkas Arov should have been called Cha’yos Ra’os (wild animals) but “Arov” means being all mixed-up and crazy. And those wild animals entered Mitzri homes to show the Mitzri that his home is like a wild mix of crazy animals, without Tz'niyus and rules.
