Or HaChaim on Deuteronomy 8:9/אור החיים על דברים ח׳:ט׳

1 ארץ אשר לא במסכנות תאכל בה לחם, "a land in which you will not eat bread out of scarceness;" Moses mentions this as there are people, even wealthy people, who always practice the lifestyle of poor people. They may be motivated by one of two reasons. 1) They are afraid they may lose their wealth and find themselves impoverished, forced to curtail their lifestyle. They prefer not to live in accordance with their wealth so that any eventual forced adjustment would be easy for them as they had never indulged themselves in the first place. 2) They do not want to appear wealthy and arouse envy. Moses says אשר לא במסכנות, "where there is no scarceness," to teach the Israelites that both of the reasons mentioned for adopting the lifestyle of the poor do not apply in ארץ ישראל. The two considerations we mentioned were based on the assumption that the society is divided into "haves" and "have nots." This will not be the case in ארץ ישראל because לא תחסר כל בה, "no one will lack anything therein." If our wealth would derive from sources outside the land of Israel there would be a reason for the considerations we mentioned. Some people would make an effort to get rich, others would not. Accordingly, there would be class distinctions after a while. Seeing the source of wealth is the land of Israel itself, everyone has equal access to it and there is no need to fear becoming impoverished or to attract the envy of the less fortunate. Moses says: כל בה, "it contains all (that anyone desires)."

2Moses singles out two examples of the earth's natural wealth which the land of Israel is blessed with, i.e. iron and copper. The reason Moses singles out these two examples is because they are basic to everybody's needs. After this (verse 10) Moses mentions that people would eat and be satisfied, etc. The reason Moses had to mention this cardinal fact was that the perfection of the land does not merely consist of its fruit, its harvests, but the land must also provide basic materials to enable its people to build their shelters and to generally provide the possibility of life in the city. Many successful farmers in various countries who employ outside labour, etc., nonetheless are forced to sell all their produce in order to acquire building materials, clothing and tools. To teach us that the land of Israel would not lack natural resources Moses adds the words לא תחסר כל בה, that nothing essential would be scarce in this land after he had described the seven most valuable foods and fruit the land would produce.