378. Halachos l'Moshe MiSinai of Tefillin

Tefillin, Mezuzah v’Sefer Torah 1:2

A mezuzah contains two passages: Deuteronomy 6:4-9 and Deuteronomy 11:13-21. If even one letter is missing a point, the mezuzah is invalid. Similarly, if a Torah scroll is missing even a single letter, it is invalid.

Tefillin, Mezuzah v’Sefer Torah 1:3

Tefillin require ten things, all of which are halachos l’Moshe MiSinai – laws communicated to Moses at Mount Sinai. They are all obligatory so if one deviates from them in any way, the tefillin are invalid. Two of these rules involve the writing of the tefillin and eight involve their coverings and the tying of their straps. The two rules about their writing are that they must be written in ink and they must be written on parchment.