Hashem Can Always Send Goodness:
Sefer Divrei Yisroel explains the question of “what will we eat in the seventh year” by saying that it certainly would be good not to worry and to rely on Hashem to provide; however, it is not easy for everyone to do this. A rich man who has money put away and has business dealings he can rely on will find it easy not to worry, but the pasuk is speaking about people who say “what will we eat if we don’t plant and don’t harvest?” These are people who have no source of income if they don’t work their fields and no savings put away for a rainy day. How can they avoid worrying?
The Torah is coming to strengthen the resolve of these people and to assure them that Hashem will take care of them by sending an abundant harvest in the sixth year, which will last for three years.
