We fully expect to farm the land "by the sweat of our brow", and we do so for six consecutive years. On the seventh, however, we are instructed to leave the land fallow, to give it a "Sabbath". Today, modern agricultural science confirms that this practice allows the earth to restore nutrients for future growth, but in Biblical times this took an enormous leap of faith. However, we are NOT instructed to make no effort. The six years are to be front-ended, and that work is very concrete. Furthermore, the sabbatical year is not one of passive "flopping", but of focused, directed faith in G*d.
7 Blessed is he who trusts in the Lord,Whose trust is the Lord alone.8 He shall be like a tree planted by waters,Sending forth its roots by a stream:It does not sense the coming of heat,Its leaves are ever fresh;It has no care in a year of drought,It does not cease to yield fruit."Work as though it all depends on you; Pray as though it all depends on G*d."