Reply Obj. 1: That which is so by its essence takes precedence of that which is so through another, wherefore the goodness of the measure which has the mode essentially, takes precedence of the goodness of the thing measured, which has its mode through something else; and so too, charity, which has a mode as a measure has, stands before the other virtues, which have a mode through being measured.
Reply Obj. 2: As Augustine adds in the same passage, "the measure of our love for God is to love Him with our whole heart," that is to love Him as much as He can be loved, and this belongs to the mode which is proper to the measure.
Reply Obj. 3: An affection, whose object is subject to reason's judgment, should be measured by reason. But the object of the Divine love which is God surpasses the judgment of reason, wherefore it is not measured by reason but transcends it. Nor is there parity between the interior act and external acts of charity. For the interior act of charity has the character of an end, since man's ultimate good consists in his soul cleaving to God, according to Ps. 72:28: "It is good for me to adhere to my God"; whereas the exterior acts are as means to the end, and so have to be measured both according to charity and according to reason. _______________________
SEVENTH ARTICLE [II-II, Q. 27, Art. 7]
Whether It Is More Meritorious to Love an Enemy Than to Love a Friend?
Objection 1: It would seem more meritorious to love an enemy than to love a friend. For it is written (Matt. 5:46): "If you love them that love you, what reward shall you have?" Therefore it is not deserving of reward to love one's friend: whereas, as the same passage proves, to love one's enemy is deserving of a reward. Therefore it is more meritorious to love one's enemy than to love one's friend.
Obj. 2: Further, an act is the more meritorious through proceeding from a greater charity. But it belongs to the perfect children of God to love their enemies, whereas those also who have imperfect charity love their friends. Therefore it is more meritorious to love one's enemy than to love one's friend.
Obj. 3: Further, where there is more effort for good, there seems to be more merit, since "every man shall receive his own reward according to his own labor" (1 Cor. 3:8). Now a man has to make a greater effort to love his enemy than to love his friend, because it is more difficult. Therefore it seems more meritorious to love one's enemy than to love one's friend.
On the contrary, The better an action is, the more meritorious it is. Now it is better to love one's friend, since it is better to love a better man, and the friend who loves you is better than the enemy who hates you. Therefore it is more meritorious to love one's friend than to love one's enemy.
I answer that, God is the reason for our loving our neighbor out of charity, as stated above (Q. 25, A. 1). When therefore it is asked which is better or more meritorious, to love one's friend or one's enemy, these two loves may be compared in two ways, first, on the part of our neighbor whom we love, secondly, on the part of the reason for which we love him.