Paul was not apologetic about equating the freewill offerings of God's people as part of the debt they owed for receiving the priceless truths of eternal life. God expects tangible, physical fruit from his people as well as invisible spiritual results. He expects the people who benefit from the gospel to do their fair share in helping extend that message to others. Today, we call this brotherly sense of obligation, stewardship. It is a term with honorable biblical precedents behind it.
Financial stewardship furnishes the fuel for all our other ministries.
How much money can be raised is a secondary objective. Our contributions are not by themselves an infallible index to what we treasure in this life, but giving is not a minor matter unrelated to our spiritual lives either. Jesus himself spoke on this subject often and in precise terms. Jesus and giving Jesus included the giving of alms in his Sermon on the Mount. But when you give to the needy, do not let your left hand know what your right hand is doing, so that your giving may be in secret.