Only be selfish

Selfishness is a term used to refer negativity. It is considering oneself as the priority. However, this is the most important tool for a sadhaka, (or one practicing sadhana). Note carefully:
Selfishness has both negative and positive approaches. Negative selfishness is usually the act of satisfying oneself by causing inconvenience to the other. Here the intention is to satisfy our senses by causing harm to the other soul.

This is an act of devils. At the same time, selfishness is the most important tool for progressing in spirituality. As always, spirituality is the practice of rising to the conscious planes. This includes conscious living, association, talking, etc. Selfishness in this case is the only tool that helps safeguard one's spiritual practice. Without it one cannot avoid associating with material people or the ones who engage in satisfying the senses.

A spiritual man disassociate from the world, his relatives and his friends. Only if one uses selfishness to serve this purpose can one really be called a spiritualist. This is the highest peaks of selfishness but the purest of all. Only this step can invoke the Lord unlike the selfishness used to satisfy the senses. Only this extent of selfishness can get one to the first stage of spirituality.