You have multiplied the nation, and not increased the joy: they joy before you according to the joy in harvest…
To a commercial people the expression is not so significant as it would be to a Jew. The Jews were essentially an agricultural people. God did not encourage them to trade with surrounding nations, lest they should fall into idolatry; and so we find that they were not a manufacturing community, and, except in the time of Solomon, they made no pretensions to a navy. The arts and sciences were but little cultivated; but the fields and vineyards gave them abundant occupation, and the soil and climate were favourable to the growth of the corn and the vine. God took special interest in their agricultural pursuits. He laid down minute laws respecting sowing and gleaning, and He reminded the people in the feasts which He appointed that they were dependent on Him for the gift of food, and should receive it with a devout and thankful heart. It has been well observed respecting the three chief Jewish festivals that one opened the harvest, the second marked a stage in it, and the third closed it. Joy occupied an important place in the religion of the Jews; and never, I suppose, was it so loud in its expression as at the Feast of Tabernacles, when they looked upon their full granaries, and brought in the last clusters of their fruitful vines.
(F. J. Austin.)
Parallel VersesKJV: Thou hast multiplied the nation, and not increased the joy: they joy before thee according to the joy in harvest, and as men rejoice when they divide the spoil.