Our American culture wants us to serve money. The Bible says we can't do that and serve God at the same time. Matthew 6:24 says:
No one can serve two masters. Either you will hate the one and love the other, or you will be devoted to the one and despise the other. You cannot serve both God and money.
Why did God say that? He could have said “you can’t serve God and power” or you can’t serve “God and satan.” So why did He say "God and money" because He knew that for many of us money would be the number one competitor for our hearts.