Menachot 32 – How to Write a Mezuzah

The last words of the mezuzah - “on the earth” - must appear alone on the line. Some take it to mean at the end of the line, so that “heaven” appears directly over “earth,” to indicate that your days be prolonged like the height of heaven over the earth. Others say that it means at the beginning of the line, so that “earth” is as far as possible away from “heaven,” to indicate that the days of your life be prolonged like the heaven is far from the earth.

If a Torah scroll wore out it may not be made into a mezuzah by cutting out the two required paragraphs, sewing them, and affixing them to the doorpost, because we may not lower objects in sanctity but only bring them up. So lowering in sanctity is the only problem, but if not for that, we could? What about the requirement to write the mezuzah on the outer, tougher part of the skin? - That is only the preferred procedure.

In addition, mezuzah requires scoring with thin lines before writing, and it does not have to be copied from a text, because everyone knows it by heart.

Art: Johann Hamza - An Old Man Reading