Some people have peculiar habits when they pray in the synagogue. Some pray out loud and disturb the people around them. Others have an annoying practice of not remaining in one place but are constantly pacing back and forth. Both of these habits are halachicly and socially unacceptable.
Rabbi Chaim of Brisk (Harav Soloveitchik’s grandfather) could not tolerate worshipers who prayed out loud. He brought support for his position from this week’s Portion. We are told that at the bottom of the robe the Kohen Gadol had to wear, were attached gold bells. The Torah explains the purpose of these bells. It says: VENISHMA KOLO BEVO’O EL HAKODESH, “…and its sound shall be heard when he enters the Sanctuary…” (Ex. 28,35)
Rabbi Chaim points out that if the Kohen Gadol were reciting his prayers out loud there would be no need for bells. Hence it is obvious that he said them quietly and so should we.
Furthermore, another Rabbi pointed out that in Pirke Avot we learn that one of the miracles that took place in the Bet Hamikdash was that although it was crowded when the people were standing there, when they had to bow down miraculously there was plenty of room. The Rabbi asked why was there not a miracle also that when they were standing there should also be plenty of room. The reason he gave was that if there were lots of room people would be walking back and forth which would be unbecoming for conduct in the Bet Hamikdash. This is also not appropriate behavior in a synagogue.
While the above explanations may have been said with tongue in cheek, they do express true notion.