1) The holy Doctor finds these different notions in Sacred Scripture and tradition, and he had therefore to explain them all as to their theological significance in due order.

2) These notions are of themselves subordinated as in the present enumeration beginning from the more universal and ascending to the less universal, and they all presuppose Christ's charity, which holds the first place. For Christ's act of charity is primarily meritorious, but it is strictly satisfactory only if it is laborious and difficult; for every satisfactory act is meritorious, but not vice versa. Then an act that is both meritorious and satisfactory is not always in the strict sense a sacrifice, whereas, on the contrary, a perfect sacrifice, such as a holocaust, is both meritorious and satisfactory. Moreover, in the enumeration, redemption is taken in the restricted sense of liberation from the slavery of sin and the devil, but not in the complete sense, whereby Christ is said to be the cause or the author of our salvation. Wherefore several authors explain this question of St. Thomas, as we shall, by considering the different ways of redemption in the adequate sense, that is, by way of merit, satisfaction, sacrifice, liberation, and effectiveness. But in this enumeration, as E. Hugon observes, merit, satisfaction, and sacrifice belong to redemption as constitutive elements, but our liberation and the efficiency of our salvation in the application of the merits and satisfaction of the Passion, belong to it as consecutive elements or effects. Thus the orderly arrangement of these articles and the beautiful structure of this question become increasingly apparent. But the liberation and restoration of the human race is called objective redemption, and to this Jesus has condign right, the Blessed Virgin Mary, however, a congruent title. The application of this liberation and restoration to this particular person, such as to Peter or Paul, is called subjective redemption.

3) Finally, Christ the Savior in redeeming us practiced different subordinated virtues. First of all, He practiced charity, to which merit strictly belongs, for the other virtues are meritorious only as they are commanded by charity. Secondly, He practiced justice, of which satisfaction is a part. Thirdly, He practiced religion, to which sacrifice belongs. But these three elements, as stated, constitute the work of redemption from which our liberation and restoration follow, by the effective application of the merits and satisfaction of the Passion. Thus St. Thomas succeeded very well in the orderly arrangement of this question. It is no wonder that this question is rather complex, because the higher and more universal is the cause, the more it includes several modes of causality; but in this complexity shines forth the splendor of its unity, inasmuch as all these elements manifest Christ's love for the Father and for us.