A reader in New York writes:

Dear Rabbi,

I recently read in a renowned Jewish weekly, an explanation for why Tefillin are not worn all-day nowadays, even though the Mitzva of wearing them is all day long. I read in the press that people began to wear Tefillin so that they would be considered honest and trustworthy in peoples' eyes. Some would take advantage of this trust to steal, cheat and swindle. If this is so, why aren't other external signs of piety also minimized in order to protect the innocent?

Truly yours

Dear "Truly yours",

Your question is excellent. You always have to be careful about what your read, even if it appears in well-known, respected newspapers.

The real reason that Tefillin are not worn all day today is for a different reason altogether! It is because a person's body and mind must be "clean" (halachically speaking) while the Tefillin are on the person. See the Shulchan Aruch, Orach Chayim, 37:2 and the commentaries there where this reason is clearly stated, and the necessary parameters are described. This requirement of "cleanliness" is extremely difficult to fulfill, and therefore Tefillin should not be worn all day (with rare individual exceptions).

The source and story quoted in your newspaper do not constitute a halachically binding reason for not fulfilling the Mitzva throughout the day. Rather, they teach us that one should be careful not to be convinced of a person's honesty and righteousness solely based on the fact that the person wears Tefillin (see Tosafot, Tractate Shabbat 49a, "K'Elisha..."). This would indeed seem to equally apply to other external signs of piety, such as a headcovering, modest clothing, Mezuza-kissing, and the like. Trust is a factor of a person's inner nature which can best be measured according to the person's character traits.