Our Reason For Placing Mezuzah
There is a plethora of material dealing with the reasons for placing a mezuzah on our doors. The added benefits of security, blessings and health, BUT our reason for placing them on our door posts, is because we were commanded to do so by G-d. That is a major principal in our performance of "mitzvos". Sure, the benefits are great, but that should not be our main reason for their performance.
There are many books specifically dealing with the laws of how each letter should be written, and if there is a change in the appearance ; laws regarding fading letters; laws regarding letters that are ambiguous how are they to be ascertained etc, etc.... It is for this reason, a mezuzah should be purchased from a reliable source. That means, from a source that knows where the mezuzah was written, and that it was indeed written by a G-d fearing man.
Mezuzos
Mezuzos: In the book of Devorim chapter 6 verse 9, and chapter 11, verse 20, G-d commands us to write a mezuzah on our doorways by attaching them to the door posts. All doors are included in this obligation except for the lavatory.
Each mezuzah must be hand written by a certified scribe (sofer). Each letter has a specific form to conform to. No letter is allowed to touch any other letter. Equally important is the intent (kavana) one has when the mezuzah is being written. If the mezuzah was written without the intent of writing a kosher mezuzah and for sake of a mezuzah, in may not be usable. By looking at the mezuzah one could not tell that. Only the writer or scribe knows that! That is why the scribe must be scrupulously religious.
