8:7 Paul does one of those nice things in Greek we cannot do in English. We must translate his phrase regarding love something like this: The love in us for you. More literally it is "the of you in us love." The "us" and "you" are enveloped into the word love almost!
8:7 Paul just uses the word "grace" (charis) here to reference the act of kindness/financial giving. "This grace" is what he calls it!
8:8 Again Paul has some odd constructions possible in Greek. He literally writes: "The the of love sincerity to test." In other words, the object of the testing is not the love, but it is the sincerity...
8:9 Here we see how Paul again is connecting grace and money: Paul talks about the grace of Jesus Christ showing how he became impoverished (listerally, one who begs, ptoocheia)
8:10 With this sentence I may have reached my limits of understanding Greek grammar; This verse has a bunch of translations which basically boil down to where you put the punctuation in the Greek, which wasn't there in the beginning anyway. The question is, what is Paul trying to highlight: The will to give or the completion of the giving. In either case, Paul is making the point: You gave, you even wanted to give, so go ahead and finish it up. What is the advantage of those three? Unclear...
8:11 Paul is using a bunch of articular infinitives here...the last of which is "ek tou echein" which means "from the having..." The sentence literally reads: "Complete the doing in order that just as the desire of willing, so likewise the completeing from the having." I would argue that this goofy construction in Greek emphasizes the verbal nature of the having; in short, it is not "from your means" as in your are drawing a from a storage chest, but rather, it is from your having, your constant action of having.
8:12 I may really be afar here, but Paul spells it out a bit differently than the translators want to make it. Paul never says "What you have" Paul simply says, "if the desire is there, as much as one is having acceptably, and not as one does not have." I think like most parts of 2 Cor, this passage probably demands more thorough attention, but I think it is fair to say that Paul emphasizes the act of having rather then the possession they actually own. I think by doing this, he moves from the gift to the giver.
8:14 Paul here uses the word abundance as a noun (perisseuma); he uses this as a verb in the beginning of the section (vs. 7). His appeal, then, is bracketed by abundance.