Prohibition on charging interest makes perfect sense in a zero growth economy. Economic growth was effectively zero per capita for almost all of human history before the industrial revolution. Wealth amassed from charging interest in a zero growth economy represents transfer of wealth, not capital formation.

Likewise, sabbath keeping rules make perfect sense in such an economy. No, you can't work a lot of extra hours more than we're all willing to work and amass extra wealth for yourself. The net result of that is you taking a bigger piece of the economic pie. The longer work really doesn't grow the pie, which was essentially limited by the agricultural productivity of the land.