Compare their lives of luxury to the life of Our Lord, Jesus Christ. He really is God in flesh, but think about how He entered this world, and how He lived during the time of His humiliation. What a difference! Read the Gospels, and see for yourselves.
Listen to this hymn and think about the words. It is based on part of 2 Corinthians 8:9, "For you know the grace of our Lord Jesus Christ, that though he was rich, yet for your sake he became poor, ..."
Notice that he did not start out poor and then make Himself rich by coming to earth. He is the Creator of everything, so everything is His by right. However, He set all of that aside for our sake. He is the example of giving, not the example of how to make yourself rich at others' expense.
There are wealthy people who spend great amounts of their fortunes helping those less fortunate. They are rich, but they give so that others might also be cared for. There are many good charities that depend on the generosity of people, even wealthy ones. It is best, though, to give to local charities or through your local church. It is easier that way to see how people actually live and easier to track how the money is actually being used. Do NOT send your money to the people on TV! That goes for the Hollywood benefit productions, too, as well as the Red Cross, maybe.
It is not especially godly to be poor, or ungodly to be rich, but there are some obvious examples of people making themselves rich off the preaching of the Gospel, or off of other forms of charity work.
Anyway, here is the wonderful hymn Thou Who Wast Rich.: