Stewardship is a way of life that flows from gratitude. We are called to share a portion of:
To give 10% of one's first fruits to God, is called tithing and it is the way our ancestors in the faith expressed their gratitude to God for all they had received. Tithing is the Biblical norm.
Today the Church asks its members to be stewards. On the one hand this means we are to care for our world, ecologically speaking. It also means that we are called to give sacrificially of our time, talent in addition to our treasure.