I answer that, Every act should be proportionate both to its object and to the agent. But from its object it takes its species, while, from the power of the agent it takes the mode of its intensity: thus movement has its species from the term to which it tends, while the intensity of its speed arises from the disposition of the thing moved and the power of the mover. Accordingly love takes its species from its object, but its intensity is due to the lover.
Now the object of charity's love is God, and man is the lover. Therefore the specific diversity of the love which is in accordance with charity, as regards the love of our neighbor, depends on his relation to God, so that, out of charity, we should wish a greater good to one who is nearer to God; for though the good which charity wishes to all, viz. everlasting happiness, is one in itself, yet it has various degrees according to various shares of happiness, and it belongs to charity to wish God's justice to be maintained, in accordance with which better men have a fuller share of happiness. And this regards the species of love; for there are different species of love according to the different goods that we wish for those whom we love.
On the other hand, the intensity of love is measured with regard to the man who loves, and accordingly man loves those who are more closely united to him, with more intense affection as to the good he wishes for them, than he loves those who are better as to the greater good he wishes for them.
Again a further difference must be observed here: for some neighbors are connected with us by their natural origin, a connection which cannot be severed, since that origin makes them to be what they are. But the goodness of virtue, wherein some are close to God, can come and go, increase and decrease, as was shown above (Question [24], Articles [4],10,11). Hence it is possible for one, out of charity, to wish this man who is more closely united to one, to be better than another, and so reach a higher degree of happiness.
Moreover there is yet another reason for which, out of charity, we love more those who are more nearly connected with us, since we love them in more ways. For, towards those who are not connected with us we have no other friendship than charity, whereas for those who are connected with us, we have certain other friendships, according to the way in which they are connected. Now since the good on which every other friendship of the virtuous is based, is directed, as to its end, to the good on which charity is based, it follows that charity commands each act of another friendship, even as the art which is about the end commands the art which is about the means. Consequently this very act of loving someone because he is akin or connected with us, or because he is a fellow-countryman or for any like reason that is referable to the end of charity, can be commanded by charity, so that, out of charity both eliciting and commanding, we love in more ways those who are more nearly connected with us.