Love is an activity, not a passive affect; it is a "standing in", not a "falling for".
In the most general way, the active character of love can be described by stating that love is primarily giving, not receiving. The most important sphere of giving, however, is not that of material things, but lies in the specifically human realm.
What does one person give to another? He gives of himself, of the most precious thing he has, he gives of his life. This does not necessarily mean that he sacrifices his life for the other—but that he gives him of that which is alive in him; he gives him of his joy, of his understanding, of his knowledge, of his humor, of his sadness—of all expressions and manifestations of that which is alive In him. In thus giving of his life, he enriches the other person, he enhances the other's sense of aliveness by enhancing his own sense of aliveness. He does not give in order to receive; giving is in itself exquisite joy. But in giving he cannot help bringing something to life in the other person, and this which is brought to life reflects back to him; in truly giving, he cannot help receiving that which is given back to him. Giving implies to make the other person a giver also and they both share in the joy of what they have brought to life, in the act of giving, something is born, and both persons involved are grateful for the life that is born for both of them.
Specifically with regard to love this means: love is a power which produces love; impotence is the inability to produce love, this thought has been beautifully expressed by Marx: "Assume," he says, "man as man, and his relation to the world as a human one, and you can exchange love only for love, confidence for confidence, etc. If you wish to enjoy art, you must be a person who has a really stimulating and furthering influence on other people. Every one of your relationships to man and to nature must be a definite expression of your real, individual life corresponding to the object of your will. If you love without calling forth love, that is, if your love as such does not produce love, if by means of an expression of life as a living person you do not make of yourself a loved person, then your love is impotent, a misfortune."
