Isaias 58:10

He says then to them again concerning these things, “Why do ye fast to Me as on this day, saith the Lord, that your voice should be heard with a cry? I have not chosen this fast, saith the Lord, that a man should humble his soul. Nor, though ye bend your neck like a ring, and put upon you sackcloth and ashes, will ye call it an acceptable fast.” To us He saith, “Behold, this is the fast that I have chosen, saith the Lord, not that a man should humble his soul, but that he should loose every band of iniquity, untie the fastenings of harsh agreements, restore to liberty them that are bruised, tear in pieces every unjust engagement, feed the hungry with thy bread, clothe the naked when thou seest him, bring the homeless into thy house, not despise the humble if thou behold him, and not [turn away] from the members of thine own family. …

“Learn, therefore, to keep the true fast of God, as Isaiah says, that you may please God. Isaiah has cried thus: ‘Shout vehemently, and do not spare: lift up thy voice as with a trumpet, and show My people their transgressions, and the house of Jacob their sins. They seek Me from day to day, and desire to know My ways, as a nation that did righteousness, and forsook not the judgment of God. They ask of Me now righteous judgment, and desire to draw near to God, saying, Wherefore have we fasted, and Thou seest not? and afflicted our souls, and Thou hast not known? Because in the days of your fasting you find your own pleasure, and oppress all those who are subject to you. Behold, ye fast for strifes and debates, and smite the humble with your fists. …

7. For it is Thou, Lord, that judgest me; for although no “man knoweth the things of a man, save the spirit of man which is in him,” yet is there something of man which “the spirit of man which is in him” itself knoweth not. But Thou, Lord, who hast made him, knowest him wholly. I indeed, though in Thy sight I despise myself, and reckon “myself but dust and ashes,” yet know something concerning Thee, which I know not concerning myself. And assuredly “now we see through a glass darkly,” not yet “face to face.” So long, therefore, as I be “absent” from Thee, I am more “present” with myself than with Thee; and yet know I that Thou canst not suffer violence; but for myself I know not what temptations I am able to resist, and what I am not able. …

19. “I will confess to the Lord according to His justice” ( ver. 17 ). This is not the sinner’s confession: for he says this, who said above most truly, “If there be iniquity in my hands:” but it is a confession of God’s justice, in which we speak thus, Verily, O Lord, Thou art just, in that Thou both so protectest the just, that Thou enlightenest them by Thyself; and so orderest sinners, that they be punished not by Thine, but by their own malice. This confession so praises the Lord, that the blasphemies of the ungodly can avail nothing, who, willing to excuse their evil deeds, are unwilling to attribute to their own fault that they sin, that is, are unwilling to attribute their fault to their fault. …