Stewardship is explained this way by the Archdiocese of St. Louis:
Stewardship Is What God Calls Us to Do
Throughout sacred scripture God calls us to be a giving people. The concepts of giving God our “first fruits” and of tithing a fair percent were first mentioned in the Old Testament. About half of Our Lord’s parables address the proper use of our resources and Jesus talks about money five times more than He talks about prayer. Generous giving is fundamental to our faith tradition. Any parish that truly wants to follow the teachings of Our Lord must teach and embrace stewardship. As the US Catholic Bishops write in their Pastoral Letter on Stewardship, Stewardship: A Disciple's Response, "Once one chooses to become a disciple of Jesus Christ, stewardship is not an option."
Stewardship Is What Built Our Church
From the awe-inspiring European basilicas to the smallest rural churches in our own country, all of the churches, schools, hospitals and other Catholic agencies which we take for granted today have been built by previous generations giving generously of their time, talents and treasure. Auctions, raffles and golf tournaments did not build up the Church and they cannot maintain it. The Church today was built up because our ancestors in faith understood their responsibility to support the establishment of God's kingdom here on earth. They made God a priority in their lives and they generously shared no matter how much or how little they had.