No branch can bear fruit by itself; it must remain in the vine.
I. The incompatibility of love and egoism
II. God: the essence of Love
III. Love in Christianity
IV. An Example
I. Egoism or egotism is the habit of valuing everything in reference to one's personal interest. Egoistic means pertaining to or of the nature of egoism. Therefore, an egoistic love is a love pertaining to or of the nature of egoism. In other words, it is a love that is valued in reference to one's personal interest. An act of love whose fundamental purpose is salvation in the afterlife is valued in reference to one's personal interest. Therefore, it is an egoistic love. But it is a conceptual truth that any act of love is altruistic, since it is, by definition, concerned for or devoted to the welfare of others. Hence, an act of love whose fundamental purpose is salvation in the afterlife is egoistic and hypocritical. Strictly speaking, it is not even love by nature. To conclude, any worldview teaching you that you acquire your own salvation, by yourself, through your good deeds, does not teach you love, but self-seeking.
One may argue that, although their worldview teaches them such an idea, they love because this is where their emotions lead them. However, firstly, it is empathy that is manifested here, and not love. Every human being has empathy as a result of their moral values. But not everyone has love. Secondly, the subconscious controls 95% of the brain. This being said, it is your fundamental beliefs that determine who you are, wether you like it or not, and wether you are aware of it or not. Thus, if you are taught that good deeds are what lead you to heaven, then self-seeking is unconsciously the very basic motivation that makes you want to love.
II. Sequentially, and as a matter of fact, pure love is unattainable by humans whose principal characteristics include egoism or self-seeking. In order for it to be true and sincere, love has to be free from egotism with which it is incompatible.
In opposition to humans, God is ontologically perfect and is the essence of Love itself. Thus, His Spirit is the only source of love.
III and IV. In the comment section.