Albert Barnes on 2 Corinthians 8:1

Moreover, brethren, we do you to wit. We make known to you; we inform you. The phrase, "we do you to Wit," is used in Tindal's translation, and means, "we cause you to know." The purpose for which Paul informed them of the liberality of the churches of Macedonia was to excite them to similar liberality.

Of the grace of God, etc. The favour which God had shown them in exciting a spirit of liberality, and in enabling them to contribute to the fund for supplying the wants of the poor saints at Jerusalem. The word "grace" (χαριν) is sometimes used in the sense of gift, and the phrase "gift of God" some have supposed mast mean very great gift, where the words "of God" may be designed to mark anything very eminent or excellent, as in the phrase "cedars of God," "mountains of God," denoting very great cedars, very great mountains. Some critics (as Macknight, Bloomfield, Locke, and others) have supposed that this means that the churches of Macedonia had been able to contribute largely to the aid of the saints at Judea. But the more obvious and correct interpretation, as I apprehend, is that which is implied in the common version, that the phrase "grace of God" means that God had bestowed on them grace to give according to their ability in this cause. According to this it is implied,

(1.) that a disposition to contribute to the cause of benevolence is to be traced to God. He is its Author. He excites it. It is not a plant of native growth in the human heart; but a large and liberal spirit of benevolence is one of the effects of his grace, and is to be traced to him.

(2.) It is a favour bestowed on a church when God excites in it a spirit of benevolence. It is one of the evidences of his love. And indeed there cannot be a higher proof of the favour of God, than when by his grace he inclines and enables us to contribute largely to meliorate the condition, and to alleviate the wants of our fellow-men. Perhaps the apostle here meant delicately to hint this. He did not therefore say coldly that the churches of Macedonia had contributed to this object, but he speaks of it as a favour shown to them by God that they were able to do it. And he meant, probably, gently to intimate to the Corinthians that it would be an evidence that they were enjoying the favour of God, if they should contribute in like manner.

The churches of Macedonia. Philippi, Thessalonica, Berea. For an account of Macedonia, Acts 16:9; Rom 15:26. Of these churches, that at Philippi seems to have been most distinguished for liberality, (Php 4:10,15,16,18,) though it is probable that other churches contributed according to their ability, as they are commended (comp. 2Cor 9:2) without distinction.

(*) "to wit" "We make known to you" (a) "churches of Macedonia" 2Cor 9:2,4