"Woe to you, teachers of the Law and Pharisees, you hypocrites! You clean the outside of the cup and dish, but inside they are full of greed and self-indulgence. Blind Pharisee! First clean the inside of the cup and dish, and then the outside also will be clean."
Jesus taught that we needed to be washed and cleansed from the inside out. Greed and self-indulgence are only two things Jesus mentions, but they have a common link. They both are evidence of selfishness. The one who is greedy cares only for his own provision and possession and not for others. Someone who is self-indulgent is focused solely on their own pleasure to the exclusion of those who live in misery. They turn a blind eye to those who are in poverty and who suffer. They eat cake and ice cream while starving children want only bread and water.
How detrimental is that old line "I deserve this, I've earned it, I need to treat myself every once and a while" to receiving grace? Is $9 spent on a 2 hour movie better spent that 2 hours chatting with a homeless man over a $9 meal? How can we preach what we do not practice? What good is it if everyone else believes it but you don't believe it?
Jesus called us to wash the inside of the cup and be justified and sanctified by his blood. However, he still wants us to wash the outside of the cup too.