Paul writes this chapter to goad the Corinthians into following through with a pledge they had made to give to the poor Christians in Jerusalem (2 Cor. 9; 1 Cor. 16.1-4). As Paul traveled and preached the gospel, he was also asking Gentile churches to give to a fund to support the Jerusalem church which had fallen on hard times. To encourage the Corinthians to make good on their promises, he uses the Macedonian Christians as an example.
Read the text carefully. You will notice that the Macedonians gave out of poverty, not wealth. Though Paul was reluctant to mention his collection because of their own suffering, the Macedonians pleaded and begged to participate in this offering (2 Cor 8.1-4).
Can you imagine it? When's the last time you've heard of Christians begging to participate in an offering. Most of the time, Christians resent any mention of a need in church. But these Macedonians, though lacking in wealth and comfort, wanted to give to support the Jewish Christians in Jerusalem.
But more remarkable still is the language Paul employs to describe the action of the Macedonian churches. Notice, Paul begins by describing the grace of God given to the Macedonian Christians. Then, he continually refers to the offering as a "grace" in the original language, Greek (NSRV: vs. 4--privilege (grace); vs. 6--generous undertaking (grace); vs. 7--generous undertaking (grace); vs. 19--generous undertaking (grace), cf. footnotes in your Bible). To summarize this theme Paul refers to the "'generous act' (grace) of our Lord Jesus Christ, that though he was rich, yet for your sakes he became poor . . ." (vs. 19)
To me that places the concept of giving in another realm altogether. In light of God's grace and the grace that has been given to us we're called to participate in the grace of giving, of sacrificing for others and for the common good.
With that in mind, I find myself agreeing with many others who argue that a 10% tithe is merely a good starting point--just a beginning to teach us and shape us so that we might begin to grasp the grace of giving sacrificially. After all, to give in a manner that reflects grace certainly requires us to no longer give merely out of our leftovers. Rather we must grow in stewardship so that our giving actually points to what God has done for us in Christ Jesus.
Wow! I have some thinking and praying to do. I hate when I convict myself.
Peace.