The Shema is one of the most significant sections of Scripture in the Hebrew Bible, and it is recited daily by Jews today in morning prayers.
Deuteronomy 6:4-9 4 “Hear, O Israel: The LORD our God, the LORD is one. 5 You shall love the LORD your God with all your heart and with all your soul and with all your might. 6 And these words that I command you today shall be on your heart. 7 You shall teach them diligently to your children, and shall talk of them when you sit in your house, and when you walk by the way, and when you lie down, and when you rise. 8 You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes. 9 You shall write them on the doorposts of your house and on your gates.
A mezuzah is a small parchment with two sections of Torah written on it, the Shema and the Vehaya in Deut. 11:13-21. Both of these passages contain the verse, “You shall write them on the doorposts of your house and on your gates” (Deut. 6:9; 11:20). From the instruction in these passages, many Jews hang a mezuzah from their doorpost encased by a wooden box to remind them of this passage.
I’m not a Jew, but I am a Christian who holds up the Hebrew Scriptures as God-breathed and profitable. So, I bought a mezuzah and hung it on my door. As I pass through the door, I recite as much of this passage as I can in Hebrew, and I am reminded of the great proclamation of the God of Israel, my ultimate purpose to love him with my whole being, and the importance of the word of God. I have previously taken some Hebrew classes, and lately I have been trying to keep up with my Hebrew with regular readings. I have found the mezuzah, along with other Hebrew prayers and blessings to be a helpful reminder and a great encouragement.
I might mention one other fact. As with much else in Judaism, the placement and use of the mezuzah is steeped in tradition. According to Jewish tradition, the mezuzah is placed diagonally. I heard that this goes back to a dispute between rabbis as to whether it should be vertical or perpendicular. Being unable to end the dispute, they compromised and placed it diagonally next to the doorpost.