I think most of us have heard or read about ministries that "never ask for money". Usually this observation is made with a muted condemnation of any ministry that does ask for money. The implied message is: if God approves of a ministry, He'll supply the need without many fundraising. That sounds impressive. But for most ministries, God expects us to labour in fundraising. Paul is a case in point.
Chapter 8 is all about fundraising. As you read it carefully, you see Paul doing his utmost to stimulate generosity in the Corinthian church. He refers to the Macedonian churches who gave generously in spite of their "extreme poverty" (v.2). He talks of their eagerness to participate in "the privilege of sharing in this service to the saints" (v.4 NIV). He then urges the Corinthians to do the same (v.6) and commends them for their excellence "in everything" (v.7a) — (Paul seems to have forgotten, for the moment, their lack of excellence in morality). He follows this with a comment that their generosity will be a "test" of "the sincerity of [their] love" (v.8) — and says he'll "compare it with the earnestness of others" (how would you respond to this kind of pressure from your pastor?).
The urgency of Paul's appeal reflects a great concern on his part for the ongoing health of the financially poorer congregations. In a sense, you might say Paul's intensity reflects his sense of "ownership" —he's committed, and appeals not for himself, but for "the saints". Maybe this is exactly the kind of pressure we should invite rather than resist. It's a challenge to our will.
That's why we need a "willing mind", one that is committed first to the kingdom of Heaven. A mind that will choose to give "according to what one has".