“3. If you follow My statutes and observe My commandments and perform them,
4. I will give your rains in their time, the Land will yield its produce, and the tree of the field will give forth its fruit.
5. Your threshing will last until the vintage, and the vintage will last until the sowing; you will eat your food to satiety, and you will live in security in your land.” —Leviticus 26:3-5
So if you follow, observe, and perform, the Lord will take care of you. Anyone who has been around for a few days on Earth knows that sometimes this is not the case. We can say that the individual didn't really do the work. Or we can say that they might not get material rewards from following the rules, but that they would get spiritual strength from the connection with G_d they acquired from their good work.