In short, luck does you no good. Intention always counts.
1 Now, it is obvious from the foregoing that it is possible to sin in two ways. One way is such that the mental intention is entirely broken away from the order to God, Who is called the ultimate end of all good people; and this is mortal sin.
The second way is such that, while the ordering of the human mind to the ultimate end remains, some impediment is brought in whereby one is held back from freely tending toward the end; and this is called venial sin.
So, if there must be a difference of punishments depending on a difference of sins, it follows that he who commits a mortal sin must be punished in such a way that he may be cut off from the end of man, but he who sins venially must not be punished so that he is cut off but so that he is retarded or made to suffer difficulty in acquiring the end.
For, thus is the equality of justice preserved: in whatever way man voluntarily turns away from his end by sinning, in the same way in the order of punishment, involuntarily, he is impeded in regard to the attainment of his end.
Notes Plus, do not assume all your sins are venial.
2 Again, as will is in men, so is natural inclination in the things of nature. Now, if the inclination toward its end be taken away from a natural thing, it becomes altogether unable to reach its end. For example, when a heavy body loses its weight through corruption and becomes light, it will not reach its proper place.
But, if there be an impediment to its motion, while its inclination to the end remains, then, when the obstacle is removed, it will reach its end.
Now, in the man who commits a mortal sin, the intention of his will is completely turned away from his ultimate end; while in the man who commits a venial sin, his intention continues to be fixed on the end, but he is somewhat hindered in that he improperly fixes his intention on the means to the end. Therefore, for the one who sins mortally, this is the proper punishment: to be completely cut off from the attainment of the end. But for the one who sins venially, he must suffer some difficulty before he reaches the end.
Notes The analogy of the sin is apter than you think. Mortal sin removes and corrupts. The old saying is that sin makes you stupid. You therefore have to seek restoration.
3 Besides, when a person obtains some good that he did not intend, this is due to fortune and chance. So, if he whose intention is turned away from the ultimate end is to attain the ultimate end, this will be due to fortune and chance. But this is not right. In fact, the ultimate end is a good of the understanding.
Now, fortune is repugnant to understanding, since fortuitous events occur apart from the ordering of understanding. Moreover, it is not appropriate for the understanding to attain its end in an unintelligent manner. Therefore, he will not attain his ultimate end who, by sinning mortally, has his intention turned away from the ultimate end.
4 Moreover, matter does not get its form from the agent unless it be disposed to the form. Now, the end or the good is a perfection of the will, just as form is for matter. Hence, the will is not going to obtain its ultimate end unless it be appropriately disposed. But the will is disposed toward its end by the intention and desire for the end. Therefore, he whose intention is averted from the end will not obtain that end.
5 Furthermore, in the case of things ordered to an end, the relationship is such that, if the end occurs or will occur, then the means to the end must also be available, but if the means to the end are not available, then the end will not occur. For, if the end can occur even without the presence of the means to the end, it is futile to seek the end by such means.
But it is admitted by all men that man, through works of virtue, among which the chief one is the intention of the proper end, may attain his ultimate end which is felicity. So, if a person acts against virtue, with his intention turned away from the ultimate end, it is fitting that he be deprived of his ultimate end.
Notes Meditate on “fitting that he be deprived of his ultimate end.”
6 Hence, it is said, Matthew (7:23): “Depart from me, all you who work iniquity.”