Deuteronomy 6:9

“And thou shalt write them upon the posts of thine house, and on thy gates.] To put them in mind of them when they went out and came in, that they might be careful to observe them; this the Jews take literally also, and write in a scroll of parchment this section with some passages; and, as the Targum of Jonathan here, fix them in three places, over against the bed chamber, upon the posts of the house, and on the gate at the right hand of it; and this is what they call the Mezuzah; and the account given of it is this. In a parchment prepared for the purpose, they write the words in (<050604>Deuteronomy 6:4-9 11:13-20) and then roll up the parchment, and write on it “Shaddai”; and put it…”

“By adopting and regulating customary usages (e. g. Egyptian) Moses provides at once a check on superstition and a means of keeping the Divine Law in memory. On the “frontlets,” the “phylacteries” of the New Test. Matthew 23:5, see Exodus 13:16. On Deuteronomy 6:9; Deuteronomy 11:20 is based the Jewish usage of the mezuzah. This word denotes properly a door-post, as it is rendered here and in Exodus 12:7, Exodus 12:22; Exodus 21:6 etc. Among the Jews however, it is the name given to the square piece of parchment, inscribed with Deuteronomy 6:4-9; Deuteronomy 11:13-21, which is rolled up in a small cylinder of wood or metal, and affixed to the right-hand post of every door in a Jewish house.…”

“6:9 Write them on the doorposts: In later Judaism, people placed portions of Deuteronomy in a small metal case (a mezuzah) attached to the doorframes of houses or other buildings. It was customary to touch the mezuzah when passing through the doorway to show respect for and dependence upon the Scripture.”

“Deu 11:20; Exo 12:7; Job 19:23-25; Isa 30:8, Isa 57:8; Hab 2:2 Deuteronomy 6:10”