This week we read פרשת קרח. We are told that קרח was the richest man in the world. There is even an expression used in spoken Hebrew, עשיר כקרח, as wealthy as קרח, to describe a very rich person.
The message here is that we be warned of how horrible the מידה of קנאה, jealousy, can be. One who allows himself to be jealous of another person, removes from himself the possibility of ever being happy. His obsession with another person, consumes him. His own wealth and success is of insignificance to him. All that matters to him, is what this other person is doing.
Korach is a prime example of this. He had wealth and prominence, but could not stand seeing his cousins, Moshe and Aharon, having a higher position than him.
If one has a tendency towards jealousy, he needs to really work on himself to overcome it. He must learn to be happy with his own lot in life. This is the way to achieve happiness and contentment.