After trying to help us understand that we must give, but do so cheerfully, lesson five reminds us that free-will giving is "God's Plan for the Support of His Church." Many seem to feel that a congregation "runs" without money, but money is needed to do the Lord's work. Each member giving from his/her livelihood is the Lord's plan for supporting the work.
For example, if we are to fulfill the Great Commission (Matthew 28:18-20), we will either need our own money or we will need to give money to support others willing to go to other lands, or who are willing to give up a secular profession to preach locally. There are dozens of other needs for financial support, and every member should see these needs.
I don't want to give away too much of this lesson, but it's basic purpose is to take a brief survey of giving throughout the three dispensations of the Bible (Patriarchy, Mosaic, Christian). While this may be a basic lesson, it helps us see the importance of giving from the very beginning.
Finally, the chapter ends with a quick reminder to not just give, but do so with the right attitude. While this has been mentioned in the book before, it needs to be emphasized at this point, because we need to avoid giving "just because others have in the past."