We proceed to the eighth article thus:

1. It seems that a man cannot merit an increase of grace or charity. For when one has received the reward which one has merited, one is not entitled to any other reward. Thus it is said of some in Matt.6:2: "They have their reward." Hence if anyone were to merit an increase of grace or charity, it would follow that he could not expect any other reward, once this increase was granted. But this is impossible.

2. Again, nothing acts beyond its own species. Now it is clear from what was said in Arts.2 and 4 that the principle of merit is either grace or charity. It follows that no man can merit grace or charity greater than that which he already possesses.

3. Again, everything that a man merits, he merits by each and every act which proceeds from grace or charity, since each and every such act merits eternal life. Hence if a man merits an increase of grace or charity, it seems that he merits it by any act of charity whatsoever: and if subsequent sin does not prevent it, everything that is merited is inevitably received from God, since it is said in II Tim.1:12: "I know whom I have believed, and am persuaded that he is able to keep that which I have committed unto him." It follows that grace or charity must be increased by each and every meritorious action. But this seems impossible, since meritorious actions are sometimes not very fervent, and insufficient for an increase of charity. Increase of charity cannot therefore be merited.

On the other hand: Augustine says (Tract.5 in Joan.): "Charity deserves to be increased, so that when increased it may deserve to be perfected." Increase of grace or charity is therefore merited.

I answer: as we said in Arts.6 and 7, that to which the moving of grace extends is merited condignly. Now the moving of a mover extends not only to the final term of a movement, but also to the whole progress of the movement. The final term of the movement of grace is eternal life, and progress in this movement is by increase of charity or grace, according to Prov.4:18: "the path of the just is as the shining light, that shineth more and more unto the perfect day." It follows that increase of grace is merited condignly.

On the first point: reward is indeed the final term of merit. But there are two kinds of term in a movement. There is a final term, and also a mediate term which is both beginning and term at once. Now the reward of an increase of grace or charity is a mediate term. But a reward of man's favour is a final term for those who set their heart on it. That is why they receive no other reward.

On the second point: an increase of grace is not beyond the power of grace already received, although it is quantitatively greater, just as a tree is not beyond the power of its seed, although greater in size.

On the third point: a man merits an increase of grace by each and every meritorious action, just as he thereby merits the consummation of grace, which is eternal life. But just as eternal life is granted not immediately, but in its own time, so is an increase of grace granted not immediately, but in its own time, that is, when a man is sufficiently well disposed to receive it.