Midrash su Deuteronomio 15:17

4) "you shall not wrong, one man, his brother": This refers to wronging with money. — But perhaps it refers to wronging with words? "And you shall not wrong, one man, his fellow" (Devarim 15:17) already speaks of wronging with words. How, then, am I to understand "you shall not wrong, one man, his brother"? As wronging with money.

"and he shall bring him near to the door or to the door-post": The door is being compared to the door-post, viz.: Just as a door-post stands in its place, so, the door must be standing in its place. And this would follow a fortiori, viz.: If the door, which is not kasher for the mitzvah (of mezuzah), is kasher for boring, then the door-post, which is kasher for the mitzvah of mezuzah, how much more so should it be kasher for boring! It is, therefore, written (Devarim 15:17) "Then you shall take the awl and place it in his ear and in the door" — You place it in the door, but not in the door-post. But perhaps the awl is to pierce both his ear and the door-post; it is, therefore, written (Exodus 21:6) "then his master shall bore his ear with an awl" — his ear is pierced and not the door. It is the first reading, then, which is to be accepted — The door is being compared to the door-post, viz.: Just as a door-post stands in its place, so, the door must be standing in its place.

(Devarim 15:17) "Then you shall take the awl and place it": Whence is it derived that also valid for this purpose are thorn, glass, and reed haulm? From "then you shall take" (anything that lends itself to "taking." These are the words of R. Yossi b. R. Yehudah. Rebbi says: Just as an awl is distinct in being of metal, so all that are of metal (may be used).