The image of the overflowing cup comes from the days of David and was a symbol of invitation, welcome, or dismissal. If a host kept the cup full, the guests knew they were welcome. If the cup was empty, not refilled, the host was indicating it was time for the guests to leave. However, if the host really enjoyed the company, he would fill the cup until overflowing and let it spill over the rim, saturating the table.
