823. Sealing a Hole

Shabbos 23:3

Just as we are not permitted to open a hole on Shabbos, we may not close a hole. Therefore, it is prohibited to seal a hole in a barrel even with something that need not be smeared or squeezed, such as a piece of wood or a small stone. One may, however, store food in the hole even though doing so seals the barrel. This is an area in which one is permitted to engage in subterfuge.

Shabbos 23:4

Any action that completes the creation of an item renders one liable for completion (“the final hammer strike”). Because of this, one who files an article or repairs it in any way would be liable. Similarly, it is prohibited to make music on Shabbos, either with an actual instrument like a harp or a lyre or with some other object. One may not even tap his fingers on the ground or on a board, or snap in tune, or shake a nut as a rattle or ring a bell for a child. All of these were prohibited as a preventive measure to ensure that one does not come to repair a musical instrument.