Paul is quick to say that he is not commanding them (v. 8). Although he has the authority to do so, he waives its exercise here. His game plan is of another sort. He seeks rather to test the sincerity of [the Corinthians'] love by comparing it with the earnestness of others (v. 8). In short, he tries to motivate them by means of some friendly competition. The term test (dokimazo) carries the positive sense of examining something to prove its worth or authenticity. The something here is sincerity. The term gnhsios means "true-born" (Büchsel 1964a) and denotes what is genuine or legitimate (Liddell, Scott and Jones 1978). The Jerusalem relief fund becomes the Corinthians' opportunity to show, as the Macedonians have done, that the love they profess toward other believers is bona fide.
Paul turns not only to the Macedonian churches to test the Corinthians' sincerity but also to Christ himself, the supreme example of generosity. It has been said that no one can outgive God. There is no better proof of this than the grace of our Lord Jesus Christ (v. 9). Grace is used in its usual sense of divine favor or goodwill to those who do not deserve it. In this case it is divine favor extended to us by Jesus Christ (subjective genitive, ten charin tou Christou). For though he was rich, yet for your sakes he became poor (v. 9). Paul is probably thinking of the riches of Christ's heavenly existence, which included equality with God and being in the form of God (Phil 2:6). But then Christ became poor. This was a voluntary action on his part. The aorist is most likely ingressive: Christ "entered into a state of" poverty. Paul undoubtedly has the incarnation in mind, when Christ gave up the "riches" of heavenly existence to assume an earthly state called "poverty."
What this state amounted to is debated. Paul could be thinking of how Jesus was born into a poor family and associated with those of low social standing. "Christ chose a stable in preference to a palace and consistently held to that even in death" (Macdonald 1986:5). This is, to be sure, an emphasis of Luke's Gospel (for example, 2:24, 6:20-26; 16:19-31). Or Paul could have in mind Jesus' identification with those who are "poor in spirit"--a stress in Matthew's Gospel (for example, 5:3, 6, 20; James D. G. Dunn). But perhaps the choice does not lie betoeen spiritual and physical poverty. If Philippians 2:7-8 is any indication, then Paul is thinking of how one to whom honor and service was due voluntarily took the form of one from whom service was expected. Indeed, he "made himself nothing, taking the very nature of a servant . . . and became obedient to death--even death on a cross." "Ordinary charity," says James Denney, "is but the crumbs from the rich man's table; but if we catch Christ's spirit, it will carry us far beyond that" (1900:268). This is Paul's hope for the Corinthians.
William Barclay aptly observes that Christ's sacrifice did not begin on the cross, nor even at birth. It began in heaven, when he laid aside his glory and consented to come to earth (1954:229). Why did he do it? He did it, Paul says, so that we through his poverty might become rich. To put it another way, Christ went from riches to rags so that we might go from rags to riches. What are these riches? Although Paul referred too verses earlier to the Corinthians' rich spiritual endowments, it is more likely that here he is thinking of the riches of salvation. No fewer than eight riches have been mentioned thus far in the letter: the down payment of the Spirit (1:22; 5:5), daily renewal (4:16), an eternal weight of glory (4:18), an eternal house in heaven (5:1), unending fellowship with Christ (5:8), new creation (5:17), reconciliation (5:18) and righteousness (5:21).