When thus it shall be; rather, for so shall it be. In the time described the condition of the earth shall be like to that of an olive-ground when the beating is done, or of a vineyard when (he grapes are gathered.
That is, a small and scattered remnant of inhabitants shall alone be left, like the few grapes and olives that were the portion of the gleaners (cf. Isaiah 17:6). There shall be. These words are not needed, and should be erased.
The nexus is, "so it shall be as the shaking [rather, 'beating'] of an olive tree."