2 Corinthians 9:1-5

There is no need for me to write to you about this service to the saints. For I know your eagerness to help, and I have been boasting about it to the Macedonians, telling them that since last year you in Achaia were ready to give; and your enthusiasm has stirred most of them to action.

(v1-2, NIV)

Paul doesn't even need to tell them about this. He already has confidence in them that they will follow through. Paul has even been boasting about them.

But I am sending the brothers in order that our boasting about you in this matter should not prove hollow, but that you may be ready, as I said you would be.

(v3, NIV)

Paul has been going on boasting about them. However, they have yet to prove themselves in this matter. They still have yet to give generously as Paul has boasted. He has confidence in them, but the fact remains that they still haven't fully proven themselves. The boasting is really quite empty if the person you're boasting about hasn't proven themselves yet. You can boast about some friend of yours who can do something really amazing like spit a seed a distance of 10 meters. They may believe you or they may not. But if you keep on boasting about it for a long time, sooner or later, they'll want to see it. So, Paul is hoping to give them a chance to give sooner rather than later.

For if any Macedonians come with me and find you unprepared, we—not to say anything about you—would be ashamed of having been so confident. So I thought it necessary to urge the brothers to visit you in advance and finish the arrangements for the generous gift you had promised. Then it will be ready as a generous gift, not as one grudgingly given.

(v4-5, NIV)

Paul might even become ashamed of them if they don't follow through. However, they will be given the opportunity and hopefully Paul's boasting was not an empty one.

The point is also made about not giving grudgingly. The gift should be given joyfully like the Macedonians (2 Cor 8:2).

So I thought it necessary to urge the brothers to go on ahead to you and arrange in advance for the gift you have promised, so that it may be ready as a willing gift, not as an exaction.

(v5, ESV)

The notes in my bible say this about the word "exaction" in verse 5: "Or a gift expecting something in return; Greek greed". Not only should they give joyfully, but part of proper giving means not expecting anything in return. If you did expect something in return, you're not actually giving. If you expect something in return, it becomes a payment. Therefore, it can no longer be a gift or something given.