Do horses run on rocks?

In chapter 6, Amos the prophet of God to the elite in Samaria, sounds a final blow those who consider themselves right with God.  This ironic question posed by Amos goes to the center of a calcified people, who were called out to be light to the world, a nation of priests, yet had turned the sweet justice of God into wormwood.  Those who were the recipients of grace were to be natually the covenant people of God, but they tragically had fallen into luxury, and perverted the covenant. 

How can we as covenant people of God fall prey to luxury?  And how does luxury affect our perceived rightness with God and our love for neighbor?