2. Personal and communal development would be threatened if the true scale of values were undermined. The desire for necessities is legitimate, and work undertaken to obtain them is a duty: "If any man will not work, neither let him eat". But the acquiring of temporal goods can lead to greed, to the insatiable desire for more, and can make increased power a tempting objective. Individuals, families and nations can be overcome by avarice, be they poor or rich, and all can fall victim to a stifling materialism. Increased possession is not the ultimate goal of nations nor of individuals. All growth is ambivalent. It is essential if man is to develop as a man, but in a way it imprisons man if he considers it the supreme good, and it restricts his vision. Then we see hearts harden and minds close, and men no longer gather together in friendship but out of self-interest, which soon leads to oppositions and disunity. The exclusive pursuit of possessions thus become an obstacle to individual fulfillment and to man's true greatness. Both for nations and for individual men, avarice is the most evident form of moral underdevelopment. (Papal Encyclical, Populorum Progressio, 26 Mar 1967).