294. Walking Behind a Shul

Tefillah u’Birkas Kohanim 5:15

The universal practice is not to recite Tachanun on Shabbos or yom tov, nor on Rosh Hashana, Rosh Chodesh, Chanukah or Purim, nor in mincha on the day before these days. Tachanun is never recited in maariv, though some individuals do so. Only on Yom Kippur do we recite the tachanunim in every service because Yom Kippur is a day for supplications.

Tefillah u’Birkas Kohanim 6:1

One is not permitted to walk behind a shul while the congregation is praying unless he is carrying a burden or there are two entrances on different sides of the shul. In such a case, anyone who sees him will assume that he might be entering the shul through the other entrance. The same applies if there are two shuls in town, since observers would assume that he is going to the other shul. If one is wearing tefillin, he is permitted to walk behind a shul without meeting any of these other conditions since the tefillin indicate that he is a person who is seriously interested in the performance of commandments and not one to refrain from prayer.