Rasul Allah (sal Allahu alaihi wasallam) said: "Richness does not lie in the abundance of (worldly) goods, but richness is the richness of the soul (heart,self)." [Muslim]
There are millionaires who are obsessed with making more money,always worried that their wealth is not going to be enough for them.Their insecurity does not let them enjoy what they are blessed with. Such a person despite having riches cannot be called a rich person. For what good is wealth that does not allow its possessor to feel rich,secure or happy/ True wealth is the wealth of contentment. This is a gift from Allah (subhana wa ta'ala) and it lives as contentment in the heart of a person.