How does a believer decide how much to give?
A believer decides giving by grace, not law: give as the Lord leads and lays it on the heart, not by legal binding or set rules. Giving corresponds to how God has prospered, and believers first give themselves to the Lord.
Les explains that He expects the saints to give as He leads them to give, not with any legal binding or legal ramifications that you will give this, but under grace. In Corinthians, giving is as God has prospered you, as the Lord lays it on your heart, and not according to a set of rules and regulations. The believers first gave themselves to the Lord, stepping into God's saving grace, and then opened themselves to the Apostle Paul and his ministry. Titus was desired to finish the same grace, gathering offerings for the poor saints.