This is an excerpt from our free booklet, Our Sin and Our World.
But frequently one and the same sin is also a sin such as is both a punishment, and a cause of sin. We shall make this more plain, by bringing forward some instances. For unrestrained gluttony excites the fulness of the flesh to the heat of lust. But lust, when committed, is frequently concealed either by perjury or murder, for fear it should be punished by the vengeance of human laws. Let us suppose to ourselves then, that a man has given the reins to his gluttony, that, being overcome by his gluttony, he has committed the sin of adultery, that being detected in adultery, he has secretly murdered the husband of the adulteress, lest he should he brought to judgment. This adultery then, standing between gluttony and murder, springing from the one, and giving being to the other, is a sin, and both the punishment, and the cause of sin also. It is in truth a sin of itself, but the punishment of sin, because it has increased the guilt of gluttony; but it is the cause of sin, because it also gave birth to the subsequent murder. One and the same sin, then, is both the punishment of the preceding, and the cause of the subsequent, sin: because it both condemns past sins, while it adds to their amount, and sows the seeds of future sins, to deserve condemnation.
Image: Gregory the Great by Francisco Goya (1796–1799) (Source).