Charity is defined as the habit by which God becomes the object of our love. However, God could become the object of a kind of private love, such as that of a lover intolerant of any other lovers besides himself (as for example in the case of a jealous man in love with a woman). But a habit of this kind would be both inordinate and imperfect.
It would be inordinate because God, the good of all, does not want to be the private good of any one person, not does right reason allow one person to appropriate to himself this common good. It follows that a love that tends to regard this common good exclusively as its own property, neither to be loved nor possessed by any other, is an inordinate love.
It would also be imperfect because a person who loves perfectly wants his beloved to be loved. Therefore God, in infusing the habit of charity by which the soul tends towards Him in an orderly and perfect way, gives a habit by which He is loved as the common good to be co-loved by others as well. And thus this habit which is of God, leads an individual to want God to be held dear and to be loved also by others.
Therefore, just as this habit leads a person to love God in Himself in an orderly and perfect way, so also it leads him to want God to be loved not only by the person himself but also by anyone else whose friendship is pleasing to Him.
It is clear from this how the habit of charity must be single and undivided, because it does not concern itself in the first instance with a plurality of objects, but with God alone as the primary object and as the first good. Secondarily it then wants God to be loved and to possessed in love by everyone else to the utmost of his power, because it is in this that a perfect and orderly love of God consists. And in willing this, I love both myself and my neighbor in charity, willing, that is, for both of us the desire and the possession of God in Himself through love.
Hence it is evident that it is by one and the same act that I want God and that I want you to want God. And in this my love is a love of charity, because out this love I desire a good for you which is due to you in justice.
For this reason, my neighbor is not to be regarded as a second object of charity but rather as an object that is entirely incidental, because he is someone who is capable of co-loving the Beloved with me in a perfect and orderly way; and I love him precisely so that he can become a co-lover. In this I love him as it were incidentally, not for himself, but because of the object which I want to be co-loved by him. And in wanting that object to be co-loved by him, I implicitly want what is good for him because it is due to him in justice.
