G‑d told the Jews that the animal they were to eat this night would be called the “Passover” animal. He gave them further instructions regarding how they were to prepare it and eat it.
Preparing for Personal Redemption
וּלְקַחְתֶּם אֲגֻדַּת אֵזוֹב . . . וְהִגַּעְתֶּם אֶל הַמַּשְׁקוֹף וְאֶל שְׁתֵּי הַמְּזוּזֹת מִן הַדָּם אֲשֶׁר בַּסָּף וגו': (שמות יב:כב)
[G‑d instructed Moses to tell the people,] You must take a bundle of hyssop and [with it] apply some of the blood [of the Passover animal] to the lintel and the two doorposts. Exodus 12:22

The right doorpost signified good deeds; the left doorpost signified prayer, and the lintel above them signified the study of the Torah. Together, these three constitute a complete, balanced life that enables us to fulfill our Divine mission of making the world into G‑d’s home.

The door itself signified our readiness to obey G‑d’s will, since this commitment is the entrance into our active partnership with G‑d to rectify the world. The lowly hyssop used to apply the blood to the door frame signified the self-abnegation we must cultivate in order to be receptive to G‑d’s presence in our lives. The blood itself signified the vitality of our animating soul, with which we must perform good deeds, pray, and study the Torah.

Every personal exodus from an “Egypt” requires that we humbly apply our vitality to action, prayer, and study of the Torah, all performed with renewed commitment to our Divine mission in life.1