From where do we
know that one must have respect and awe for a Shul?
From the verse in
this week's Parashah: "He should not enter all times into the Holy" (Vayikra 16:2). One may enter only when he is full of awe of
Hashem within his soul.
This is why Nadav
and Avihu were punished! It is true that
they entered the Mishkan and we are discussing a Shul, but a Shul is called
"Mikdash Me'at" – a minituare Temple.
In our times, to our great distress, we do not have the Temple, so the
Shul is Hashem's Temple.
It is permissible
to jump, laugh and fool around (a little), but not in Shul. This is a holy place.