Jamieson, Fausset and Brown on Amos 9:13

13. the days come--at the future restoration of the Jews to their own land.

ploughman shall overtake ... reaper ... treader of grapes him that soweth--fulfilling Le 26:5. Such shall be the abundance that the harvest and vintage can hardly be gathered before the time for preparing for the next crop shall come. Instead of the greater part of the year being spent in war, the whole shall be spent in sowing and reaping the fruits of earth. Compare Is 65:21-23, as to the same period.

soweth seed--literally, "draweth it forth," namely, from the sack in order to sow it.

mountains ... drop sweet wine--an appropriate image, as the vines in Palestine were trained on terraces at the sides of the hills.