"Not that we are sufficient of ourselves to think any thing as of ourselves." We are not sufficient to communicate the Spirit, truth, or grace, of God to men; nor sufficient to discern, read, think, or judge, aright of a work of grace upon the hearts of men.
"But our sufficiency is of God." Our light, knowledge, grace, that we have, are of God's free gift; and so is all the success that has attended our labours. And, as for our discernment into your hearts, and knowledge of the goodness of your state, they are of God also; which he gives us light to see; and knowledge to judge of, and a persuasion in our own hearts that our judgment of you is true. Moreover, he told me "to speak boldly at Corinth, for he had much people in that city." And it was by us that ye were called. God may use others, even men of one talent, graceless men, to cast a little light upon his word, and on your minds, and to furnish his spiritual exchangers with some sound expressions for prayer and conversation; but he never uses nor honours these in converting souls to himself; for, "if ye have ten thousand instructors, ye have not many fathers; I have begotten you," through the gospel; therefore our sufficiency is of God.