Yes, it's good to work hard and be wise with your money. But God doesn't promise us financial blessings. God can bless those who follow him closely but those blessings aren't necessarily financial. God doesn't promise to make us rich. This is more what the New Testament says:
(James 2:5 NIV) Listen, my dear brothers: Has not God chosen those who are poor in the eyes of the world to be rich in faith and to inherit the kingdom he promised those who love him?
(2 Corinthians 11:27-28 NIV) I have labored and toiled and have often gone without sleep; I have known hunger and thirst and have often gone without food; I have been cold and naked. {28} Besides everything else, I face daily the pressure of my concern for all the churches.
There are some people who want to be Christians because they see it as a way to get rich. They're dead wrong.