In the Bible, the word mezuzah simply meant “doorframe, threshold,” occurring a total of eighteen times (see Exodus 12:22–23; 21:6; Deuteronomy 6:9; 11:20; Judges 16:3; 1 Samuel 1:9; 1 Kings 6:31, 33; 7:5; Isaiah 57:8; Ezekiel 41:21; 43:8 [twice]; 45:19 [twice]; 46:2; Proverbs 8:34; the plural of the word is mezuzot). Christians would be especially familiar with verses such as Exodus 12:22–23, where God commanded the Israelites in Egypt to put the blood of the sacrificial lamb on the door frames of their houses when the Passover was inaugurated. But these verses are not related to the mounting of mezuzahs in Jewish homes. Rather, the key verses are Deuteronomy 6:9 and 11:20, where God commanded the Israelites to write His commandments “on the doorframes of your houses and on your gates” (meaning, the gates of their cities; more fully, see Deuteronomy 6:4–9 and 11:18–20).
We cited these passages, above, when discussing the practice of putting on phylacteries, asking whether God commanded His people literally to keep His words before their eyes (see #20). The same question has to be asked with regard to Deuteronomy 6:9 and 11:20: Did God literally intend that His people write His words on the door frames of their houses and on their gates? It is not uncommon for Christians to have Scripture plaques in various rooms of their homes, reminding them of key promises or important ethical teachings, while believers even have a verse like Joshua 24:15, “As for me and my household, we will serve the Lord,” hanging over their front door. Is this similar to what the Lord had in mind?
There is a fascinating example from ancient Israel where archaeologists discovered an inscription actually written on the door frames of a house. What is striking is that it was a prayer addressed to Yahweh and His female deity consort! The inscription, discovered in northern Israel in the mid-1970s in what is today called Kuntillet ‘Ajrud, reads as follows: “Thus says . . . Say to Yehalle[lel], Yo‘asa and . . . I bless you [or have blessed you] to/before Yahweh of Samaria and his asherah.” This inscription reflects the rampant idolatry that existed in the northern kingdom of Samaria (see 2 Kings 17:7–17), and, in that light, it is highly unlikely that this inscription was written out of obedience to Yahweh’s Torah commandment.[81] That would really be a stretch! But this inscription may reflect a custom that was not unusual in ancient Israel, and so the command to write God’s words on the door frames or city gates could have been literally intended.
Traditional Jews, however, claim that God had something very specific in mind: They believe that the Lord wanted the Israelites to write out two key Torah passages on a tiny scroll (Deuteronomy 6:4–9; 11:13–21, two of the passages that are contained in the phylacteries) and to place these passages in a small container, called a mezuzah, which would be placed in a specific way on the door frame. This way, while the actual verses would not be seen, they would, in effect, be placed on the door frames of the houses, serving as a reminder of those verses and of God’s presence.
In keeping with the spirit of traditional Judaism, which leaves little wiggle room in the application of the commandments, the mezuzah is required to be a certain size and is to be placed on the right door frame at a certain height and at a certain angle. When a traditional Jew walks through the doorway, he touches the mezuzah with his hand and kisses it. It is common to see the Hebrew letter shin on the mezuzah, standing for Shaddai, a biblical title of God, traditionally translated “Almighty.”[82] Otherwise, the shin is placed on the back of the scroll within the mezuzah.
As to the question of why the mezuzah is affixed at an angle, the Judaism 101 website answers: “The rabbis could not decide whether it should be placed horizontally or vertically, so they compromised!”[83]