Ambrosiaster : Competent preachers ought to be unambiguous about what they say. Say nothing that is not beneficial. Given that our human will often tends in ambivalent directions, Paul is insistent that he is not acting according to his will but according to what he knows will be helpful. In Christ, of course, this problem does not exist, because he always wills what is beneficial. Furthermore, Christ's will never changes and is never uncertain. — COMMENTARY ON PAUL'S EPISTLES Augustine of Hippo : And when we confess that we have lied, we speak that which is true; for we say what we know, for we know that we lied. But that Word which is God, and can do more than we, cannot do this. For it "can do nothing except what it sees the Father do;" and it "speaks not of itself," but it has from the Father all that it speaks, since the Father speaks it in a special way; and the great might of that Word is that it cannot lie, because there cannot be there "yea and nay," but "yea yea, nay nay." Well, but that is not even to be called a word, which is not true. — ON THE TRINITY 15.15 John Chrysostom : "For the Son of God," saith he, "Who was preached among you by us, even by me, and Silvanus, and Timothy, was not yea and nay." For on this account he brings before them the company of the teachers also, as thence too giving credibility to the testimony by those who taught, and not who heard it only. And yet they were disciples; however in his modesty he counts them as in the rank of teachers. But what is, "was not yea and nay?" I have never, he saith, unsaid what before I said in the Preaching. My discourse to you was not now this, now that. For this is not of faith, but of an erring mind. "But in Him was the yea." That is, just as I said, the word abideth unshaken and steadfast. — Homily 3 on 2 Corinthians