If I do something today then it has no merit. But if I then believe in God and do exactly the same thing then it does.
The Catholic Encyclopedia (under its article on “merit”) notes that for a work to have “supernatural merit”, it must be:
- morally good;
- morally free;
- done with the assistance of actual grace; and
- inspired by a supernatural motive.
The last condition, “inspired by a supernatural motive” (ie done to please God out of love for Him) could be different depending on each person. Fr Pohle (in his work “Grace, Actual and Habitual”) (the work has the nihil obstat and imprimatur) discusses the difference between good acts done with and without a “supernatural motive”:
Sacred Scripture and the Fathers, St. Augustine included, admit the possibility of performing naturally good, though [supernaturally] unmeritorious, works (opera steriliter bona) in the state of unbelief; and their teaching is in perfect conformity with right reason.
a) Our Divine Lord Himself says: “If you love them that love you, what reward shall you have? Do not even the publicans do this? And if you salute your brethren only, what do you more? Do not also the heathens do this?” (Matthew 5:46-47) The meaning plainly is: To salute one’s neighbor is an act of charity, a naturally good deed, common even among the heathens, and one which, not being done from a supernatural motive, deserves no supernatural reward. But this does not by any means imply that to salute one’s neighbor is sinful.
St. Paul says: “For when the gentiles, who have not the law, do by nature those things that are of the law; these having not the law are a law to themselves: who shew the work of the law written in their hearts.” (Romans 2:14-15) By “gentiles” the Apostle evidently means genuine heathens, not converts from paganism to Christianity, and hence the meaning of the passage is that the heathens who know the natural law embodied in the Decalogue only as a postulate of reason, are by nature able to “do those things that are of the law,” i.e. observe at least some of its precepts. That St. Paul did not think the gentiles capable of observing the whole law without the aid of grace appears from his denunciation of their folly, a little further up in the same Epistle: “Because that, when they knew God, they have not glorified him as God, or given thanks; but became vain in their thoughts, and their foolish heart was darkened, etc.,” and also from the hypothetic form of Rom. 2:14.
continued….