There is also another reason why the aforesaid assistance of God has received the name of 'grace.' One person is said to be 'in the good graces' of another, because he is well loved by him. Now it is of the essence of love that he who loves should wish good and do good to him whom he loves. God indeed wishes and does good to all His creatures, for the very being of the creature and its every perfection is of God willing and working it (B. I, Chapp. XXIX, XXX: B. II, Chap. XV): hence it is said: Thou lovest all things that are, and hatest none of the things that thou hast made (Wisd. xi, 25). But a special tie of divine love is observable in connexion with those to whom He renders assistance, enabling them to attain the good which transcends the order of their nature, namely, the perfect fruition, not of any created good, but of God's own self. This assistance then is aptly called 'grace,' not only because it is given 'gratis,' but also because by this assistance a man comes to be, by a special prerogative, 'in the good graces' of God.
This grace, in the man in the state of grace, must be a form and perfection of him who has it.
1. That whereby a man is directed to an end must be in continual relation with him: for the mover works change continually until the body moved attains the term of its motion.* Since then man is directed to his last end by the assistance of divine grace, he must continually enjoy this assistance until he arrives at the end. But that would not be if the assistance were afforded him only as a sort of motion or passion, and not as a form abiding and, as it were, resting in him: for the movement and passion would not be in the man, except when his attention was being actually turned to the end, as is not the case continually, which is evident most of all in men asleep. Therefore the grace that puts a man in the state of grace is a form and perfection abiding in man, even when he is not actively engaged.
2. The love of God is causative of the good that is in us, as the love of man is called forth and caused by some good that is in the object of his love. But man is excited to special love by some special good pre-existent in the object. Therefore where there is posited a special love of God for man, there must consequently be posited some special good conferred by God on man. Since then the grace that constitutes the State of grace denotes a special love of God for man, there must be likewise denoted some special goodness and perfection thereby existing in man.
3. Everything is ordained to an end suited to it according to the character of its form: for of different species there are different ends. But the end to which man is directed by the assistance of divine grace is something above human nature. Therefore there must be superadded to man some supernatural form and perfection, whereby he may be aptly ordained to the aforesaid end.
4. Man ought to arrive at his last end by dint of activities of his own. Now everything is active in virtue of some form of its own. In order then that man may be brought to his last end by activities of his own, there must be superadded to him some form, to validate his activities for the gaining of his last end.
5. Divine providence provides for all according to the mode of their nature. But it is a mode proper to man to require for the perfection of his actions, over and above his natural powers, certain perfections in the shape of habits, whereby he may do good, and do it well, connaturally, readily, and pleasantly.* Therefore the aid of grace, given man by God for arriving at his last end, implies some form and perfection intrinsic to man.
Hence in Scripture the grace of God is spoken of as light: Ye were once darkness, but now light in the Lord (Eph. v, 8). The perfection whereby man is led on to his final end in the vision of God is appropriately termed light, light being the principle of vision.
Hereby is set aside the opinion of some who say that the grace of God is no positive quality in man (nihil in homine ponit), as no positive quality is ascribed to the courtier who is said to be in the good graces of the King, but rather to the King who has an affection for him. We see how this mistake arose, from failing to observe the difference between divine love and human love: for divine love is causative of the good that it loves in another, but not so human love.*
3.150 : That Man cannot merit beforehand the said Assistance
3.152 : That the Grace which constitutes the State of Grace causes in us the Love of God