What it is to sin, and to make satisfaction for sin.
Anselm. We must needs inquire, therefore, in what manner God puts away men's sins; and, in order to do this more plainly, let us first consider what it is to sin, and what it is to make satisfaction for sin.
Boso. It is yours to explain and mine to listen.
Anselm. If man or angel always rendered to God his due, he would never sin.
Boso. I cannot deny that.
Anselm. Therefore to sin is nothing else than not to render to God his due.
Boso. What is the debt which we owe to God?
Anselm. Every wish of a rational creature should be subject to the will of God.
Boso. Nothing is more true.
Anselm. This is the debt which man and angel owe to God, and no one who pays this debt commits sin; but every one who does not pay it sins. This is justice, or uprightness of will, which makes a being just or upright in heart, that is, in will; and this is the sole and complete debt of honor which we owe to God, and which God requires of us. For it is such a will only, when it can be exercised, that does works pleasing to God; and when this will cannot be exercised, it is pleasing of itself alone, since without it no work is acceptable. He who does not render this honor which is due to God, robs God of his own and dishonors him; and this is sin. Moreover, so long as he does not restore what he has taken away, he remains in fault; and it will not suffice merely to restore what has been taken away, but, considering the contempt offered, he ought to restore more than he took away. For as one who imperils another's safety does not enough by merely restoring his safety, without making some compensation for the anguish incurred; so he who violates another's honor does not enough by merely rendering honor again, but must, according to the extent of the injury done, make restoration in some way satisfactory to the person whom he has dishonored. We must also observe that when any one pays what he has unjustly taken away, he ought to give something which could not have been demanded of him, had he not stolen what belonged to another. So then, every one who sins ought to pay back the honor of which he has robbed God; and this is the satisfaction which every sinner owes to God.
Boso. Since we have determined to follow reason in all these things, I am unable to bring any objection against them, although you somewhat startle me.