I am a Jew. Hath not a Jew eyes? Hath not a Jew hands, organs, dimensions, senses, affections, passions, doorposts?
Yeah. That's a thing. Jews, traditionally, place a piece of parchment in/on the doorposts of our houses -- the outside door and many of the inside walkways between rooms. The current practice is usually to encase the hand-scribed parchment in a decorative case. We call the whole thing a "mezuzah." When we pass through an opening, we kiss the mezuzah (touch it and kiss the hand, usually, or kiss the hand then touch it). The mezuzah parchment is supposed to be a reminder of God's power and protection -- as he saved us from Egyptian slavery, he protects us from other challenges and difficulties in our lives. Kissing the holy item is a way to reinforce his presence and remember his importance.
The word mezuzah more properly refers to the doorpost, itself. The commandment comes from Deuteronomy 6:9 (and 11:20)
9. And you shall inscribe them upon the doorposts of your house and upon your gates. וּכְתַבְתָּם עַל מְזֻזוֹת בֵּיתֶךָ וּבִשְׁעָרֶיךָ
The interesting thing to me is the strange word "mezuzah." It doesn't seem connected to doors or door posts. So I looked it up.
I happen to have a copy (h/t Dad) of Ernest Klein's "A Comprehensive Etymological Dictionary of the Hebrew Language" around the house (what? you don't?). He points out the post-biblical use (the "small roll of parchment") but traces the word back to the sense of 'something standing' and the Akkadian (it's always the Akkadian with these people) "nazazu" which means "to stand" and "manzazu," door post. So there you have it -- mezuzah means "doorpost" because the language the word developed from has it mean doorpost.
I don't think that a word that has such an important place in daily religious practice can be dismissed with a simple historical connection. Something still irks me -- there had to be other ways to refer to the doorpost, other words to choose from. So why "mezuzah"? I'm going to put my own interpretation out there. Is it based in anything? No. Does it have scholarship on which to rely? Dunno. Don't care. Is it found in someone else's writing? Maybe -- I haven't checked. As far as I know, it is my idea. Take it for all in all (h/t Shakespeare).
In Hebrew, there is a word for "move" -- zuz (that's the imperative verb form). If you are taking notes, Klein connects it to the Aramaic za/tremble. There will be a test. Interestingly, one of the various derivatives is listed as tezuzah, a New Hebrew construction meaning "moving, motion." (Klein again...man this guy is good)
It seems to me that this mezuzah is then not about standing, but about moving -- when we move from place to place, when we make transitions in our lives, we must remember that our success and safety is due to a higher power. The mezuzah is about being able to go from one room, state or condition to another and invoke and rely on God's power.
As if that is't enough, I see the construction of the word as adding another dimension -- the mem prefix on the "zuz" center. The mem often indicates "the one who" (b-q-sh is "request" -- the one who requests is the mevaqesh; mevaser is the one who gives news (besorot); the teacher/one who teaches is the melamed with l-m-d being a root for learn). So the "mezuzah" seems to hint to "the one who causes to move." We are not the ones in control of our futures -- the higher power is the one who allows our moving from place to place, not just who protects us once we move. The Exodus was through God's power (and is what we are remembering via the mezuzah -- and there were no doors into the desert), not through our decision to leave. We must acknowledge God's presence and participation in even our smallest transitions by remembering via kissing the mezuzah.