The story of the widow's mite is one of the best examples of this in Scriptures. Jesus sees a great many rich people giving a lot of money to the temple treasury. He also sees a poor widow giving her last two copper coins (her mites). He uses this as a teaching moment. He says that the woman is giving more because she is giving her heart through her act of devotion. The "large sums" the rich give do not reflect the same faithful, heart-giving devotion as when the woman gives all she's got.
God doesn't want all of your money... he wants your heart. There are three things going on when you give generously in a heart-centered, living-faith way. First the act of giving recognizes that everything you have is a gift from God. Second, the act of giving puts your faith in the hope that God will continue to provide. Third, the money you give helps Christ's mission and others in need.
When Christians instead give, let's say, twenty bucks to their church occasionally on rare weeks when they have some extra money after paying bills, going shopping, and spending a few nights out, they are indeed helping through their gift. But that $20 offering is not the act of living faith because it neither recognizes all that they have is a gift, nor does it put their faith in the hope that God will continue to provide. "Truly I tell you, this poor widow has put in more than all those who are contributing to the treasury. For all of them have contributed out of their abundance; but she out of her poverty has put in everything she had, all she had to live on (Mark 12:43b-44)."
Determine how blessed you are. Take stock of your income and make a commitment to give a percentage of what you receive back. Give it to help others. Give it to the ministry of your church. When giving is done as a way of faith and a way of life, the act of giving is no longer about the money... it becomes a spiritual act of giving God your heart.
Thankful, intentional giving is living faith; and it is through living faith in Christ that we see and live the spiritual reality that surrounds us. When the world says you don't have enough, living faith reveals that God, who blessed you yesterday, will bless you again now and forever. Its an act of liberation. It's a gift of freedom.