3.Ye are the Epistle of Christ Pursuing the metaphor, he says that the Epistle of which he speaks was written by Christ, inasmuch as the faith of the Corinthians was his work. He says that it was ministered by him, as if meaning by this, that he had been in the place of ink and pen. In fine, he makes Christ the author and himself the instrument, that calumniators may understand, that it is with Christ that they have to do, if they continue to speak against him (365) with malignity. What follows is intended to increase the authority of that Epistle. The second clause, (366) however, has already a reference to the comparison that is afterwards drawn between the law and the gospel. For he takes occasion from this shortly afterwards, as we shall see, to enter upon a comparison of this nature. The antitheses here employed — ink and Spirit, stones and heart — give no small degree of weight to his statements, by way of amplification. For in drawing a contrast between ink and the Spirit of God, and between stones and heart, he expresses more than if he had simply made mention of the Spirit and the heart, without drawing any comparison.
Not on tables of stone He alludes to the promise that is recorded in Jeremiah 31:31, and Ezekiel 37:26, concerning the grace of the New Testament.
I will make, says he, a new covenant with them, not such as I had made with their fathers; but I will write my laws upon their hearts, and engrave them on their inward parts. Farther, I will take away the stony heart from the midst of thee, and will give thee a heart of flesh, that thou mayest walk in my precepts.
Paul says, that this blessing was accomplished through means of his preaching. Hence it abundantly appears, that he is a faithful minister of the New Covenant — which is a legitimate testimony in favor of his apostleship. The epithet fleshly is not taken here in a bad sense, but means soft and flexible, (367) as it is contrasted with stony, that is, hard and stubborn, as is the heart of man by nature, until it has been subdued by the Spirit of God. (368)