Job 42:6

God clearly said to him, "Do you think that I have dealt with you in any other way than that you might appear to be righteous?" That was in order, he says, to make you speak as you are speaking now, and not in order to condemn you. This is a justification for all that happened before. Actually he has not been delivered yet from his trial when he speaks so, but he is still in the midst of his torments when he makes his retraction. I attach no importance to myself, he says; I am only going to present the justification of God with regard to what has happened before. I was not even worthy of that. It is when Job has condemned himself that God justifies him. And what does he say? He has said to his friends that they must expiate their guilt and constantly calls Job his servant.

Wherefore I reproach myself. 6. For the less a person sees himself, the less is he displeased with himself; and the more he discerns the light of greater grace, the more blameworthy does he acknowledge himself to be. For when he is elevated within, by all that he is, he endeavours to agree with that standard which he beholds above him. And because human weakness still impedes him, he perceives that he differs therefrom in no slight degree, and every thing within him is burdensome, which does not agree with that inward standard. This standard blessed Job more fully beholds, as he was making progress after his suffering, and with great self-reproach is at variance with himself, saying; Therefore I reproach myself. But because there is no knowledge of reproach, if the lamentations of penitence do not also follow, it is rightly added, after the reproach, And do penance in dust and ashes. 7. For to do penance in dust and ashes, is, after having contemplated the supreme Essence, to acknowledge himself to be nothing else but dust and ashes. Whence the Lord in the Gospel says to the reprobate city, If the mighty works which have been done in you had been done in Tyre and Sidon, they would have done penance long ago in sackcloth and ashes. [Mat. 11, 21] For by 'sackcloth,' is set forth the roughness and the piercing of sin, but in 'ashes' the dust of the dead. And therefore both of these are wont to be used in penance, in order that by the piercing of sackcloth we may know what we have done through sin, and that in the dust of ashes we may consider what we have become through judgment. Let piercing sins then be considered in sackcloth, let the just punishment of sins, which succeeds by the sentence of death, be considered in ashes. For since insults of the flesh have sprung up after sin, let man behold in the roughness of the sackcloth what he has done through pride, let him behold in the ashes how far he has gone through sin. But by sackcloth can be designated also the very compunction of grief which arises from remembrance and penitence. For blessed Job in saying, I reproach myself, is wounded as it were by a kind of sackcloth, when he is galled in his mind by the sharp stings of reproaches. But he does penance in ashes; because he carefully observes what he has been made by a just judgment after his first sin, saying, I do penance in dust and ashes. As if he…