The "grace" of which Paul was writing in our text is the grace of giving! Many Christians may show diligence and love in their Christian life, but are still very reluctant to give sacrificially to the work of the Lord.
Many follow what they consider the "law of tithing" (most Christians don't even do that!) and consider this to be meritorious. The fact is, however, that giving for the Christian is not a law to be obeyed, but a grace to be cultivated.
The motivation cited by Paul for abounding in this grace was not the Old Testament ordinance, but the New Testament example in the church at Philippi. Consider, he said, "the grace of God bestowed on the churches of Macedonia; How that in a great trial of affliction the abundance of their joy and their deep poverty abounded unto the riches of their liberality. . . . beyond their power they were willing of themselves." And the real secret of their motivation was that they "first gave their own selves to the Lord" (II Corinthians 8:1-3,5). An even greater motive for abounding in this grace is the example of Christ: "For ye know the grace of our Lord Jesus Christ, that, though He was rich, yet for your sakes He became poor, that ye through His poverty might be rich" (II Corinthians 8:9).
This grace of giving is thus displayed when one gives liberally (even in times of affliction and poverty) out of whole-hearted devotion to the Lord and for the spiritual enrichment of those who are spiritually impoverished.
"God is able to make all grace abound toward you; that ye, always having all sufficiency in all things, may abound to every good work" (II Corinthians 9:8). HMM