Penance is that moral virtue by which we turn our minds from sin to God, regretting the evil we have done, endeavouring to make reparation, and purposing to sin no more. The aim of this virtue is nothing less than to reverse that law of the universe, the law of cause and effect, which makes suffering follow on transgression: speaking anthropomorphically, its aim is to appease the anger of God. Penance faces the further difficulty of retracing one's steps on the downward path, and changing formed habits and acquired appetites. It is just and reasonable that, when we know who God is and what He has done for us, we should feel shame and regret for having offended Him, whether we have done this by deliberate ingratitude or by weakness. The same habit of mind will make us sensitive to the wrongs done to God by those who belong to us as members of the same family, or nationality, or religion, or race; and it will cause us to make reparation in our own persons for their misdeeds. Hence Jesus Christ, as being of one blood with mankind, suffered shame for what His brethren had done, and impelled even by His human sentiments to offer an atonement that was not due from Him personally. You owe satisfaction for your individual wrong-doings, and for those of the race with which you form a corporate personality. It is your duty to make atonement out of the spirit of penance as did Jesus Christ.
