Ambrosiaster : Paul dismisses the charge that he cannot be trusted by telling the Corinthians that he did not change his mind lightly. He had good reasons for not doing what he had originally planned. When a spiritually minded person does not do what he intends to, it is because he has in mind something more providential for the salvation of someone's soul. The apostle did not carry out his original plan in order that the Corinthians might become better men and women. He delayed his coming specifically because there were some among them who had not purified themselves, and he was waiting for that to happen first. This is spiritual thinking. Carnal thinking, by contrast, makes changes of plan in order to suit personal desires, not in order to do what is beneficial. — COMMENTARY ON PAUL'S EPISTLES John Chrysostom : "When I therefore was thus minded, did I show fickleness?" Here in what follows, he directly does away with the charge arising out of his delay and absence. For what he says is of this nature. "I was minded to come unto you." "Wherefore then did I not come? Is it as light-minded and changeable?" for this is, "did I show fickleness?" By no means. But wherefore? "Because what things I purpose, I purpose not according to the flesh." What is, "not according to the flesh?" I purpose not "carnally." "That with me there should be the yea yea and the nay nay." But still even this is obscure. What is it then he says? The carnal man, that is, he that is rivetted to the present things and is continually occupied in them, and is without the sphere of the Spirit's influence, has power to go every where, and to wander whithersoever he will. But he that is the servant of the Spirit, and is led, and led about by Him, cannot everywhere be lord of his own purpose, having made it dependent upon the authority thence given; but it so fares with him as if a trusty servant, whose motions are always ruled by his lord's biddings and who has no power over himself nor is able to rest even a little, should make some promise to his fellow-servants, and then because his master would have it otherwise should fail to perform his promise. This then is what he means by, "I purpose not according to the flesh." I am not beyond the Spirit's governance, nor have liberty to go where I will. For I am subject to lordship and commands, the Comforter's, and by His decrees I am led, and led about. For this cause I was unable to come, for it was not the Spirit's will. — Homily 3 on 2 Corinthians