This is a common sight in ancient churches in Europe. Choir benches, made for monks or priests to stand for hours reading, praying, chanting, or whatever monks and priests did in the times when churches were primarily for prayer and not for tourists. There is a story that goes along with those solid wooden benches that are in many of these old churches.
When monks were standing for long periods of time, they were not really standing, they were crouching. Their bottoms were resting on a piece of wood that was attached to the underside of the bench. This took the pressure off their legs and helped them endure. When they were finally able to sit, they whispered to one another, ‘halte die klappe.’ In German, that means ‘hold your trap.’ To let it fall would disturb the peace of the church and ceremony, and would also give away their little trick.
So that has filtered down through the ages. ‘Hold your trap’ came from this, and so did in a very roundabout way, the more common ‘shut up.’
Thank you monks everywhere.